Replace the code for loading the 1st Page in the solution

public App()
{
InitializeComponent();

//MainPage = new MainPage();
MainPage = new NavigationPage(new Navigation.MainPage());
}

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In your XAML files

1. Add a title in your content page

2. in the Content Page Block provide a button

<Button Text="Go to 2nd Page" Clicked="Onbtn_Clicked"
BackgroundColor="Blue"/>



In your cs File (underneath your xaml file)

private async void Onbtn_Clicked(object sender, EventArgs e)
{
await Navigation.PushAsync(new MainPage2());
}