It seems you are looking for a guide related to downloading and installing a specific game (possibly Bad Guys at School) for the PPSSPP emulator on Android, with files from a site like isoroms.com. However, I must first give a strong warning:
The sandbox simulation game Bad Guys at School was originally developed for PC and released on platforms like Steam. While the original game is not natively a PSP title, various third-party sites offer modified versions or fan-made ports designed for Android and the PPSSPP emulator. Game Overview It seems you are looking for a guide
Emulation Reality: There is no official PSP (PlayStation Portable) version of Bad Guys at School. Consequently, finding a legitimate .ISO or .CSO file to run in the PPSSPP emulator is unlikely. Buy the game – Many PSP classics are
Note: There is a "PPSSPP Gold" version which is paid, but the free version works perfectly fine. Note: There is a "PPSSPP Gold" version which