diff --git a/CircleViewerMaui/App.xaml.cs b/CircleViewerMaui/App.xaml.cs
index 1d0e732..3f7204b 100644
--- a/CircleViewerMaui/App.xaml.cs
+++ b/CircleViewerMaui/App.xaml.cs
@@ -1,7 +1,12 @@
-namespace CircleViewerMaui;
+using CDPShared;
+
+namespace CircleViewerMaui;
 
 public partial class App : Application
 {
+    private static CDPWorker _cdp;
+    public static CDPWorker CDP =>_cdp;
+
     private string syncFusionLicenseKey = "MTg3MzUyM0AzMjMxMmUzMTJlMzQzMVhOUDNaUUxSMUExWTB3a1EzK294VjhKcGh3eENlanRIdXR2aWVrSGZUVTg9";
 	public App()
 	{
@@ -9,7 +14,7 @@ public partial class App : Application
 
         //Register SyncFusion license
         Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense(syncFusionLicenseKey);
-
+        _cdp = new CDPWorker();
         InitializeComponent();
 
 		MainPage = new AppShell();
diff --git a/CircleViewerMaui/AppShell.xaml b/CircleViewerMaui/AppShell.xaml
index 183d753..9955416 100644
--- a/CircleViewerMaui/AppShell.xaml
+++ b/CircleViewerMaui/AppShell.xaml
@@ -5,9 +5,15 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
     xmlns:local="clr-namespace:CircleViewerMaui"
     Shell.FlyoutBehavior="Disabled">
-
-    <ShellContent
-        ContentTemplate="{DataTemplate local:MainPage}"
-        Route="MainPage" />
+    <TabBar>
+        <ShellContent
+            Title="PDF"
+            ContentTemplate="{DataTemplate local:MainPage}" 
+            Route="MainPage" />
+        <ShellContent
+            Title="User Groups"
+            ContentTemplate="{DataTemplate local:UserGroups}" 
+            Route="UserGroups" />
+    </TabBar>
 
 </Shell>
diff --git a/CircleViewerMaui/CircleViewerMaui.csproj b/CircleViewerMaui/CircleViewerMaui.csproj
index e70390a..2afb6a2 100644
--- a/CircleViewerMaui/CircleViewerMaui.csproj
+++ b/CircleViewerMaui/CircleViewerMaui.csproj
@@ -64,4 +64,16 @@
 	  </Reference>
 	</ItemGroup>
 
+	<ItemGroup>
+	  <Compile Update="UserGroups.xaml.cs">
+	    <DependentUpon>UserGroups.xaml</DependentUpon>
+	  </Compile>
+	</ItemGroup>
+
+	<ItemGroup>
+	  <MauiXaml Update="UserGroups.xaml">
+	    <Generator>MSBuild:Compile</Generator>
+	  </MauiXaml>
+	</ItemGroup>
+
 </Project>
diff --git a/CircleViewerMaui/MainPage.xaml b/CircleViewerMaui/MainPage.xaml
index 6fb6c19..7e9ab4e 100644
--- a/CircleViewerMaui/MainPage.xaml
+++ b/CircleViewerMaui/MainPage.xaml
@@ -4,11 +4,6 @@
              xmlns:pdfViewer="http://schemas.syncfusion.com/maui"
              x:Class="CircleViewerMaui.MainPage">
 
-    <ContentPage.MenuBarItems>
-        <MenuBarItem Text="File">
-            <MenuFlyoutItem Text="Open" Clicked="onOpenClicked"/>
-        </MenuBarItem>
-    </ContentPage.MenuBarItems>
     <ContentPage.Content>
         <pdfViewer:SfPdfViewer x:Name="PdfViewer" VerticalOptions="Fill">
         </pdfViewer:SfPdfViewer>
diff --git a/CircleViewerMaui/MainPage.xaml.cs b/CircleViewerMaui/MainPage.xaml.cs
index 57dd870..6b8841a 100644
--- a/CircleViewerMaui/MainPage.xaml.cs
+++ b/CircleViewerMaui/MainPage.xaml.cs
@@ -7,7 +7,7 @@ namespace CircleViewerMaui;
 public partial class MainPage : ContentPage
 {
     int count = 0;
-    private CDPWorker _cdp;
+//    private CDPWorker _cdp;
     Timer _timer;
     Boolean _bConnected = false;
 
@@ -15,18 +15,16 @@ public partial class MainPage : ContentPage
     {
         using (LogMethod.Log(MethodBase.GetCurrentMethod().ReflectedType.Name))
         {
-            _cdp = new CDPWorker();
             InitializeComponent();
             _timer = new Timer(IsReady, null, 250, 250);
-
         }
     }
 
     void IsReady(object state)
     {
-        if (_bConnected != _cdp.Ready)
+        if (_bConnected != App.CDP.Ready)
         {
-            _bConnected = _cdp.Ready;
+            _bConnected = App.CDP.Ready;
             OnReady();
             _timer = null;
         }
@@ -76,7 +74,7 @@ public partial class MainPage : ContentPage
     {
         using (LogMethod.Log(MethodBase.GetCurrentMethod().ReflectedType.Name))
         {
-            var result = await _cdp.Decrypt(fileToLoad);
+            var result = await App.CDP.Decrypt(fileToLoad);
             if (result.Status.Result.GetValueOrDefault(false))
             {
                 byte[] buf = Convert.FromBase64String(result.DecryptedData);
diff --git a/CircleViewerMaui/UserGroups.xaml b/CircleViewerMaui/UserGroups.xaml
new file mode 100644
index 0000000..3a4493d
--- /dev/null
+++ b/CircleViewerMaui/UserGroups.xaml
@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<ContentPage
+    x:Class="CircleViewerMaui.UserGroups"
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:d="http://schemas.microsoft.com/dotnet/2021/maui/design"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:local="clr-namespace:CircleViewerMaui"
+    mc:Ignorable="d">
+    <ContentPage.Content>
+        <Grid Margin="20,20,20,20">
+            <Grid.RowDefinitions>
+                <RowDefinition Height="*" />
+                <RowDefinition Height="*" />
+            </Grid.RowDefinitions>
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="*" />
+                <ColumnDefinition Width="*" />
+            </Grid.ColumnDefinitions>
+
+            <VerticalStackLayout Grid.Row="0" Grid.Column="0" Padding="10" Margin="10" BackgroundColor="Cornsilk">
+                <Label
+                    Text="Join User Group"
+                    BackgroundColor="Purple"
+                    TextColor="White"
+                    VerticalOptions="Center"
+                    HorizontalOptions="Fill"
+                    HorizontalTextAlignment="Center"/>
+                <Label
+                    Text="Request code:"
+                    TextColor="Purple"
+                    VerticalOptions="Center"/>
+                <Entry x:Name="RequestCode" Placeholder="1234"></Entry>
+                <Label
+                    Text="Verification code:"
+                    TextColor="Purple"
+                    VerticalOptions="Center"/>
+                <Entry x:Name="VerificationCode"  Placeholder="ABCD"></Entry>
+                <Button x:Name="bnRequestVerfication" Text="Request Verification" Clicked="BnRequestVerfication_OnClicked"/>
+            </VerticalStackLayout>
+
+            <VerticalStackLayout Grid.Row="0" Grid.Column="1" Padding="10" Margin="10" BackgroundColor="Cornsilk">
+                <Label
+                    Text="User Groups"
+                    BackgroundColor="Purple"
+                    TextColor="White"
+                    VerticalOptions="Center"
+                    HorizontalOptions="Fill"
+                    HorizontalTextAlignment="Center"/>
+                <Picker x:Name="circlePicker" Title="Default User Group">
+                </Picker>
+            </VerticalStackLayout>
+
+        </Grid>
+    </ContentPage.Content>
+</ContentPage>
diff --git a/CircleViewerMaui/UserGroups.xaml.cs b/CircleViewerMaui/UserGroups.xaml.cs
new file mode 100644
index 0000000..3cff98f
--- /dev/null
+++ b/CircleViewerMaui/UserGroups.xaml.cs
@@ -0,0 +1,41 @@
+using CircleSDK.Model;
+using CommunityToolkit.Maui.Alerts;
+using CommunityToolkit.Maui.Core;
+
+namespace CircleViewerMaui
+{
+    public partial class UserGroups : ContentPage
+    {
+        public List<CircleInfo> Circles;
+        public UserGroups()
+        {
+            InitializeComponent();
+            Circles = new List<CircleInfo>(App.CDP.Circles);
+//            Circles = App.CDP.Circles;
+//            lvCircles.ItemsSource = App.CDP.Circles;
+            circlePicker.ItemsSource = App.CDP.Circles;
+            circlePicker.ItemDisplayBinding = new Binding("CircleName");
+        }
+
+        private async void BnRequestVerfication_OnClicked(object sender, EventArgs e)
+        {
+            var reply = await App.CDP.ProcessInvite(RequestCode.Text, VerificationCode.Text);
+            if (reply.Status.Result.GetValueOrDefault(false))
+            {
+                ShowToast("Failed to process request.");
+            }
+            else
+            {
+                ShowToast("Request has be submitted.");
+            }
+        }
+        async void ShowToast(string text)
+        {
+            CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
+            ToastDuration duration = ToastDuration.Short;
+            double fontSize = 14;
+            var toast = Toast.Make(text, duration, fontSize);
+            await toast.Show(cancellationTokenSource.Token);
+        }
+    }
+}