I need an example of how to accomplish Requirement VRC.Mobile.Input.3 in 2020

When the user presses the back button, the app must either go back one level in your UI or display a menu with an option to quit the app.

(https://developer.oculus.com/distribute/vrc-mobile-input-3/)

This is the last requirement I need to solve to get my app accepted. the only forum search result is here:

which is from 2 years ago and I don't think it is relevant any longer with the latest oculus integration using unity 2019.3+ and the target is Oculus Go.

Can I just see a working example of how this is accomplished in 2020? I would prefer to not make a custom exit prompt menu myself. isn't there a premade one I can drop in?

thanks