forms to native communication : i.e. data, event, object transfer

Decide page-by-page.

Xamarin.Forms is great for forms-based screens, and you can mix Xamarin.Forms with the full power of Xamarin.iOS and Xamarin.Android in the same app. For example, use Xamarin.Forms for your login and settings screens, and Xamarin.iOS and Xamarin.Android for the rest of your app

I am trying to do this, I could find a sample at https://github.com/xamarin/xamarin-forms-samples/tree/master/Forms2Native

What I also need is to transfer some data, pass on some custom events, objects.
How do i do that ? any document, sample shall greatly help

Many thanks in advance.