Index: Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreen.xaml
===================================================================
diff -u -rccd59709df29d511c5d533a068955525d12197a2 -r7942f0626806a8075b1ea3808668a20e2df2b197
--- Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreen.xaml	(.../StartScreen.xaml)	(revision ccd59709df29d511c5d533a068955525d12197a2)
+++ Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreen.xaml	(.../StartScreen.xaml)	(revision 7942f0626806a8075b1ea3808668a20e2df2b197)
@@ -27,11 +27,13 @@
                    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                    xmlns:metro="http://metro.mahapps.com/winfx/xaml/controls"
                    xmlns:properties="clr-namespace:Core.Gui.Properties"
+                   xmlns:mainWindow="clr-namespace:Core.Gui.Forms.MainWindow"
                    mc:Ignorable="d"
                    MinWidth="1366"
                    MinHeight="768"
                    Width="1366"
-                   Height="768">
+                   Height="768"
+                   d:DataContext="{d:DesignInstance IsDesignTimeCreatable=False, Type={x:Type mainWindow:StartScreenViewModel}}">
 
     <metro:MetroWindow.Resources>
         <ResourceDictionary>
@@ -119,7 +121,7 @@
                             </ScrollViewer>
                         </Grid>
                         <Grid Grid.Row="3" Margin="0 8 0 0" VerticalAlignment="Top">
-                            <Button Padding="4 8" FontSize="16">Browse</Button>
+                            <Button Padding="4 8" FontSize="16" Command="{Binding OpenProjectCommand}">Browse</Button>
                             <!-- <controls:IconButton -->
                             <!--     x:Name="BrowseButton" -->
                             <!--     Padding="4 8" -->
@@ -141,6 +143,7 @@
                                     Orientation="Horizontal" DockPanel.Dock="Left">
                             <Button Style="{StaticResource BigButtonStyle}"
                                            Tag="{x:Static properties:Resources.NewProject_DisplayName}"
+                                           Command="{Binding NewProjectCommand}"
                                            IsDefault="True">
                                 <TextBlock Text="&#xE90B;"
                                            FontFamily="{StaticResource RiskeerFont}"
Index: Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreen.xaml.cs
===================================================================
diff -u -rcf6a8a632e8f790a5bf3f25ab54d80ca0c91bc74 -r7942f0626806a8075b1ea3808668a20e2df2b197
--- Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreen.xaml.cs	(.../StartScreen.xaml.cs)	(revision cf6a8a632e8f790a5bf3f25ab54d80ca0c91bc74)
+++ Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreen.xaml.cs	(.../StartScreen.xaml.cs)	(revision 7942f0626806a8075b1ea3808668a20e2df2b197)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using MahApps.Metro.Controls;
 
 namespace Core.Gui.Forms.MainWindow
@@ -31,9 +32,19 @@
         /// <summary>
         /// Creates a new instance of <see cref="StartScreen"/>.
         /// </summary>
-        public StartScreen()
+        /// <param name="viewModel">The view model of the <see cref="StartScreen"/>.</param>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="viewModel"/>
+        /// is <c>null</c>.</exception>
+        public StartScreen(StartScreenViewModel viewModel)
         {
+            if (viewModel == null)
+            {
+                throw new ArgumentNullException(nameof(viewModel));
+            }
+
             InitializeComponent();
+
+            DataContext = viewModel;
         }
     }
 }
\ No newline at end of file
Index: Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreenViewModel.cs
===================================================================
diff -u
--- Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreenViewModel.cs	(revision 0)
+++ Core/Gui/src/Core.Gui/Forms/MainWindow/StartScreenViewModel.cs	(revision 7942f0626806a8075b1ea3808668a20e2df2b197)
@@ -0,0 +1,65 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using System.Windows.Input;
+using Core.Gui.Commands;
+
+namespace Core.Gui.Forms.MainWindow
+{
+    /// <summary>
+    /// ViewModel for <see cref="StartScreen"/>.
+    /// </summary>
+    public class StartScreenViewModel
+    {
+        /// <summary>
+        /// Creates a new instance of <see cref="StartScreenViewModel"/>.
+        /// </summary>
+        /// <param name="newProjectAction">The action to perform to create a new project.</param>
+        /// <param name="openProjectAction">The action to perform to open a project.</param>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
+        public StartScreenViewModel(Action newProjectAction, Action openProjectAction)
+        {
+            if (newProjectAction == null)
+            {
+                throw new ArgumentNullException(nameof(newProjectAction));
+            }
+
+            if (openProjectAction == null)
+            {
+                throw new ArgumentNullException(nameof(openProjectAction));
+            }
+            
+            NewProjectCommand = new RelayCommand(o => newProjectAction());
+            OpenProjectCommand = new RelayCommand(o => openProjectAction());
+        }
+
+        /// <summary>
+        /// Gets the command to create a new project.
+        /// </summary>
+        public ICommand NewProjectCommand { get; }
+        
+        /// <summary>
+        /// Gets the command to open a project.
+        /// </summary>
+        public ICommand OpenProjectCommand { get; }
+    }
+}
\ No newline at end of file
Index: Core/Gui/src/Core.Gui/GuiCore.cs
===================================================================
diff -u -r606a620901f7ed35c8be6a23d27e57096fc5269d -r7942f0626806a8075b1ea3808668a20e2df2b197
--- Core/Gui/src/Core.Gui/GuiCore.cs	(.../GuiCore.cs)	(revision 606a620901f7ed35c8be6a23d27e57096fc5269d)
+++ Core/Gui/src/Core.Gui/GuiCore.cs	(.../GuiCore.cs)	(revision 7942f0626806a8075b1ea3808668a20e2df2b197)
@@ -338,13 +338,28 @@
 
         private void ShowStartScreen()
         {
-            startScreen = new StartScreen();
+            startScreen = new StartScreen(
+                new StartScreenViewModel(OnNewProject, OnOpenProject));
             startScreen.Closed += OnStartScreenClosed;
             startScreen.Show();
 
             startScreenShown = true;
         }
 
+        private void OnNewProject()
+        {
+            StorageCommands.CreateNewProject();
+        }
+
+        private void OnOpenProject()
+        {
+            string projectPath = StorageCommands.GetExistingProjectFilePath();
+            if (!string.IsNullOrEmpty(projectPath))
+            {
+                StorageCommands.OpenExistingProject(projectPath);
+            }
+        }
+
         private void OnStartScreenClosed(object sender, EventArgs e)
         {
             ExitApplication();
Index: Core/Gui/test/Core.Gui.Test/Forms/MainWindow/StartScreenTest.cs
===================================================================
diff -u
--- Core/Gui/test/Core.Gui.Test/Forms/MainWindow/StartScreenTest.cs	(revision 0)
+++ Core/Gui/test/Core.Gui.Test/Forms/MainWindow/StartScreenTest.cs	(revision 7942f0626806a8075b1ea3808668a20e2df2b197)
@@ -0,0 +1,59 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using System.Threading;
+using Core.Gui.Forms.MainWindow;
+using MahApps.Metro.Controls;
+using NUnit.Framework;
+
+namespace Core.Gui.Test.Forms.MainWindow
+{
+    [TestFixture]
+    [Apartment(ApartmentState.STA)]
+    public class StartScreenTest
+    {
+        [Test]
+        public void Constructor_ViewModelNull_ThrowsArgumentNullException()
+        {
+            // Call
+            void Call() => new StartScreen(null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("viewModel", exception.ParamName);
+        }
+
+        [Test]
+        public void Constructor_ExpectedValues()
+        {
+            // Setup
+            var viewModel = new StartScreenViewModel(() => {}, () => {});
+
+            // Call
+            var startScreen = new StartScreen(viewModel);
+
+            // Assert
+            Assert.IsInstanceOf<MetroWindow>(startScreen);
+            Assert.AreSame(viewModel, startScreen.DataContext);
+        }
+    }
+}
\ No newline at end of file
Index: Core/Gui/test/Core.Gui.Test/Forms/MainWindow/StartScreenViewModelTest.cs
===================================================================
diff -u
--- Core/Gui/test/Core.Gui.Test/Forms/MainWindow/StartScreenViewModelTest.cs	(revision 0)
+++ Core/Gui/test/Core.Gui.Test/Forms/MainWindow/StartScreenViewModelTest.cs	(revision 7942f0626806a8075b1ea3808668a20e2df2b197)
@@ -0,0 +1,104 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using Core.Gui.Forms.MainWindow;
+using NUnit.Framework;
+
+namespace Core.Gui.Test.Forms.MainWindow
+{
+    [TestFixture]
+    public class StartScreenViewModelTest
+    {
+        [Test]
+        public void Constructor_NewProjectActionNull_ThrowsArgumentNullException()
+        {
+            // Call
+            void Call() => new StartScreenViewModel(null, () => {});
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("newProjectAction", exception.ParamName);
+        }
+
+        [Test]
+        public void Constructor_OpenProjectActionNull_ThrowsArgumentNullException()
+        {
+            // Call
+            void Call() => new StartScreenViewModel(() => {}, null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("openProjectAction", exception.ParamName);
+        }
+
+        [Test]
+        public void Constructor_ExpectedValues()
+        {
+            // Call
+            var viewModel = new StartScreenViewModel(() => {}, () => {});
+
+            // Assert
+            Assert.IsNotNull(viewModel.NewProjectCommand);
+            Assert.IsNotNull(viewModel.OpenProjectCommand);
+        }
+
+        [Test]
+        public void GivenViewModel_WhenNewProjectCommandExecuted_ThenGivenActionExecuted()
+        {
+            // Given
+            var newProjectActionCalled = 0;
+
+            void NewProjectAction()
+            {
+                newProjectActionCalled++;
+            }
+
+            var viewModel = new StartScreenViewModel(NewProjectAction, () => {});
+
+            // When
+            viewModel.NewProjectCommand.Execute(null);
+
+            // Then
+            Assert.AreEqual(1, newProjectActionCalled);
+        }
+
+        [Test]
+        public void GivenViewModel_WhenOpenProjectCommandExecuted_ThenGivenActionExecuted()
+        {
+            // Given
+            var openProjectActionCalled = 0;
+
+            void OpenProjectAction()
+            {
+                openProjectActionCalled++;
+            }
+
+            var viewModel = new StartScreenViewModel(() => {}, OpenProjectAction);
+
+            // When
+            viewModel.OpenProjectCommand.Execute(null);
+
+            // Then
+            Assert.AreEqual(1, openProjectActionCalled);
+        }
+    }
+}
\ No newline at end of file