Step 1. Right click on your MauiApp Project, Add-> New Item.

Step 2. Select Maui Content Page (XAML), and rename the page to whatever you want in this example I will call it SecondPage.

Step 3. Navigate back to your MainPage.xaml file, and add the following:

        <Button Text="Click to Navigate"
            VerticalOptions="Center"
            HorizontalOptions="Center"
            Clicked="OnBtnClicked" />

Step 4. Navigate into MainPage.xaml.cs and add the following:

private void OnBtnClicked(object sender, EventArgs e)
{
    App.Current.MainPage = new NavigationPage(new SecondPage());
}

Step 5. Compile and launch.

Conclusion: You are essentially creating a function "OnBtnClicked" within the MainPage.xaml.cs file and referencing that function into the Button component.