Look up Daijisho on the play store. It’s a front end that will organize all your roms and emulators. You probably don’t want to rely on touch controls, so depending on your preferences you could get something like a gamesir controller which your phone will fit into, or use an external controller.

This video is a good guide for setting up Android, and this one for setting up Daijisho. They’re both very exhaustive guides, his videos and website are excellent resources for anything emulation.

All you really need is a controller for it (backbone, kishi, gamesir x2) and the retroarch app. Dump your Roms to it and done. Maybe some tweaking in retroarch