While the BIOS tells the emulator how to be a PlayStation, the Plugins tell it how

Always scan downloaded plugins with VirusTotal. Older plugins are sometimes flagged by antivirus because they hook into low-level graphics processes. This is generally a false positive, but download from trusted emulation communities only.

The BIOS (Basic Input/Output System) is a copyrighted file dumped from an actual PlayStation console. Legally, you must own a physical PS1 to use these files. This article assumes you have legal rights to dump your own BIOS.