Okay heres step by step instructions for using emulators
1)download emulator of your choice(some work some don't trial and error)
2)download required bios files for your emulator gba bios for GBA scph1001.bin for psx emulator
3)download games of your choice their all free
SNES ROMS, NES ROMs, N64 ROMs, PSX ROMS, MAME ROMs, XBox 360 ROMs, Genesis ROMs, Sega Dreamcast ROMs, GBC ROMS, GBA ROMS
4)start emulator it'll ask for a bios (make sure to make a folder on sd card for all your games and bios files label it gamesrom whatever) locate the appropriate bios
5)itll show you an explorer go to gameroms folder(just an example) select game(pokemonemerald.zip) and load it
6)profits!