Most reputable emulators have a comprehensive "Quick Start Guide" that tells you exactly what files are needed and where to get them safely.
claiming to be a BIOS; these are common delivery methods for viruses. Use Ad-Blockers when visiting emulation forums.
Genuine emulators like RPCS3 will never ask you to download a "BIOS" from a third-party site. How to Safely Set Up Your PS3 Emulator
If you'd like to get started with the setup, I can help you with: Finding the Checking if your PC hardware can handle PS3 games Troubleshooting specific game settings for better FPS
To stay within legal boundaries, you should use your own physical PS3 discs. You can "dump" these games using a compatible Blu-ray drive on your PC or a custom-firmware (CFW) enabled PS3 console. Protecting Your PC