How to render Facebook-Button?

Hello, I would like to know how to render the facebook-login button from this SDK:

https://components.xamarin.com/view/facebookios

Creating the button in AppDelegate does not work (does not rendered in the storyboard and throws an exception in Main.cs)

 `LoginButton  loginButton = new LoginButton (new CGRect (48, 0, 218, 46)) {
     LoginBehavior = LoginBehavior.Native,
  };`