Navigation Controlls and Tabbed Page

Hi,

I hava a TabbedPage defined like this:

        class MainMenu : TabbedPage
            {
                public MainMenu()
                {
                    this.Title = "MyAppTitle";        
                    this.Children.Add(new NavigationPage(new MainScreen() { Title = "Main Menu" }) { Title = "Main" });
                    this.Children.Add(new NavigationPage(new Messaging() { Title = "Messaging Center" }) { Title = "Messaging" });
                }
            }

With this I am having a tabbed page with tabs titles and navigation page title, but I want to have a navigation controls to go from "Main Menu" to "Messaging Center" and viceversa.

I suppose that I must add a navigation.PushAsync and PopAsync but I don't know how. The documentation about this is very poor and have little information.
````
I appreciate any information you can give me