This is for PC version,HOLD HOTKEY BUTTON + A BUTTON you will see retroarch menu go down to DISC CONTROL then LOAD NEW DISC and you will find your psx or ps1 game. If you can’t see change it to .img not .iso Ex. COLONY.img Go to
ROMS folder, To see it! by pressing F1 on keyboard. Note:( Im using xbox controller) I hope it will help.