How to add Menu on a Desktop Forms App?

Hi, I'm studing the new features of Forms 3.x in particular the GTK support.
My demo app works, but now i want to add a classic desktop app menu (File, Edit,...).

Reading the api documentation I found this class: Xamarin.Forms.Menu and (https://docs.microsoft.com/en-us/dotnet/api/xamarin.forms.menu?view=xamarin-forms). The description say: "Represents an application menu on platforms that support them." so I think is the correct one. But there is any documentation about how to use it.

Where I can find some help to how use it?

Thanks