try navigationservices

Apollon.WPF/Views/GroupsView.xaml

@@ -0,0 +1,12 @@
+<UserControl x:Class="Apollon.WPF.Views.GroupsView"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
+             xmlns:local="clr-namespace:Apollon.WPF.Views"
+             mc:Ignorable="d" 
+             d:DesignHeight="450" d:DesignWidth="800">
+    <Grid>
+        <TextBlock Text="Gruppen" VerticalAlignment="Center" HorizontalAlignment="Center"/>
+    </Grid>
+</UserControl>