When you launch the app for the first time, it will ask for permission to access files.
If you have your ROMs on an external SD card, you must manually point the emulator to them: Arcade Version Roms : Free Download, Borrow, and Streaming mame4droid 0139u1 roms archiveorg install
Note: If you chose a custom path during setup, move them to that specific folder instead. When you launch the app for the first