UWP Prism NavigationService configuration - windows-phone

Question

I've started a UWP project with Prism Library. To navigate between pages I'm using Prism NavigationService. Well everything is ok while I have situation as in bellow image:
Well after login I need to load a window with a split view and later to use NavigationService to change only content of the "red square".
My third page xaml looks like:
<SplitView x:Name="rootSplitView" Style="{StaticResource MenuSplitViewStyle}" Grid.Row="1">
<Frame x:Name="contentFrame"/>
<SplitView.Pane>
<views:MenuViewPage/>
</SplitView.Pane>
</SplitView>
<ToggleButton x:Name="togglePaneButton"
VerticalAlignment="Center"
IsChecked="{Binding IsPaneOpen,
ElementName=rootSplitView,
Mode=TwoWay}"
Style="{StaticResource SplitViewTogglePaneButtonStyle}"
TabIndex="1" />
My app bootstrap is:
public sealed partial class App : PrismUnityApplication
{
protected override Task OnLaunchApplicationAsync(LaunchActivatedEventArgs args)
{
if (args != null && !string.IsNullOrEmpty(args.Arguments))
{
// The app was launched from a Secondary Tile
// Navigate to the item's page
//NavigationService.Navigate("ItemDetail", args.Arguments);
}
else
{
// Navigate to the initial page
NavigationService.Navigate(PageTokens.IntroPage, null);
}
Window.Current.Activate();
return Task.FromResult<object>(null);
}
...
}
My question is how I can create a region in red square and configure navigation service to use the region to navigate between pages.