Ok, so I finally found PSXLinux
(a small live-cd OS for the old PS), but apparently I have to compile the kernel to use it, and the thing is that I have no idea how to do this.
I know and have compiled software under Linux, which is actually quite simple: ./configure, make, make install, etc. But how do I do this with this kernel? and after compiling, how do I burn it as a bootable OS?