I have an update for my app that includes ActionBarSherlock with a sliding menu. I have put my navigation entirely in to the sliding menu, leaving my main_activity pretty bare. I am worried the user won't know about the menu. So I want to add a prompt at start-up that will highlight the new feature. Like this:

I am not even sure what this is called, so I don't know how to research it. Any help or suggestions will be rewarded. Thanks!