In the different platforms yes, but basically L1 opens up the left menu where you can see platforms, import games, etc... and R1 would open the right menu, which gives you platform settings when in a platform.
Also, in regards to adam1972's issue, DIG allows you to configure emulators and point them at specific android packages, since it would be a pain on your end to keep all the emulators up to date with whatever RetroArch might change. Not sure if that's something you can implement.
(Not trying to get you to be just like DIG lol. They're just the one I have the most experience with on Android, and they've had some good ideas.)