I am new to the app, and I am having difficulty with my controllers. I have a Nexus 7, and I have tried using a NES, SNES, and Xbox 360 controller via USB with not a whole lot of success. The app seems to recognize some buttons, but others don’t do anything. I would think the Xbox 360 controller would plug and play, but the majority of the buttons have no function. Is there a way to manually configure the buttons? When I go to input settings, I cannot map any of the buttons. What am I doing wrong?