Playing or not playing the sound is easy. You just wrap all code that plays a sound in an if statement that tests a Boolean. Switching the value of this Boolean is less straightforward. A button could trigger the switching of this value. To create a button you can create a Rect that you draw each frame and test for a finger press as well. On finger up in this Rect you switch the Boolean value. To create a very simple main menu screen you could use an enumeration that determines which screen the player is on: Menu, Game, Home etc and then you could vary what you draw and update each frame accordingly.