the procedure is download ps1 games from pspisoz.com then go to psp mem card ] PSP ] GAMES folder (already available) ] create a folder by the name of the game ] then paste into the file of ps1(only .cso or .iso)
for playing games u should have custom firmware.
any thing happens to your psp...im not responsible.
ive played ps1 games and its running fine.
gud luck.