how to load application main page after custom lunch screen viewcontroller

Hi All,
how to load application main page after custom lunch screen viewcontroller

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
global::Xamarin.Forms.Forms.Init();

        Window = new UIWindow(UIScreen.MainScreen.Bounds);

        var controller = new ViewController();
        controller.View.BackgroundColor = UIColor.White;

        Window.RootViewController = controller;

        // make the window visible
        Window.MakeKeyAndVisible();
      System.Threading.Thread.Sleep(15000);*///will wait for 4 seconds
       LoadApplication(new App());
        return base.FinishedLaunching(app, options);

    }

if i do like this immediately launching application without visibiling my custom launch screen uicontroller even if i put thread.sleep also it is loading application without displaying launchscreen controller .suppose if remove LoadApplication(new App()); then my launchcontroller is displaying.suppose if i remove LoadApplication(new App()); then where i need to call this(i need to navigate to application after launch screen).

  please post here if any one knows about this