@kbinthelbg This is not a MAME4Droid forum - it's a RetroPie forum. We don't include Mame4Droid in RetroPie, so you'd have more chances asking in a dedicate forum for this emulator.
Having said that - take a look a the Arcade section of the docs to understand how arcade/MAME ROMs work, then find the right ROM (and possibly BIOS files) that match your Mame4Droid version.