You wold not need retrosmc and you for the start should also not use launchers like Mame Launchers,
- You would enable Game Emulators (and their dependcies via “My Addons”
- You would add a path to your roms in the Games section of the Home screen
You then could launch games from there. Be aware that not all emulators are working (see Retroplayer (Emulators list)) and that if your roms are in ZIP’s you need to adjust the ZIP assignment (see Retroplayer (Emulators list) - #31 by joakim_s).