[Project created with Android Studio V3.4.2] [Api >= 21]
Simple overlay using RelativeLayout and TextView (help text) in the center. Buttons to back or continue.
Simple overlay, using a previous activity before launching the main screen. The view is focused (actions for the user) and help text is displayed.
Example with [ButtonFilterJava Project] (https://github.com/thaliees/ButtonFilterJava)