The homebrew plugin will automatically detect the matching .rap file inside the USB's exdata folder, copy it to the PS3’s internal hard drive ( dev_hdd0/exdata/ ), activate it, and launch the application. Method B: Using PSNpatch or reactPSN (Manual)
If you want a short how-to for creating a harmless placeholder RAP for testing with a specific PS2 Classics tool or emulator, tell me which tool you’re using and I’ll provide step-by-step instructions. Ps2 Classics Placeholder Rap File