I'm not a coder of ePSXe, but I can tell you a few things:
1.- ePSXe is NOT an open source project
2.- Now suppose that ePSXe is open source, if you say you are new in C, maybe this is not the correct project to start with, because this piece of software is an high level of development, it could be really hard to understand it to you.
3.-This is a PSX emulator NOT a PS2 emu, so it CAN'T use any plugin for PS2 emus.
And if you still want to study about PSX emulation, why don't look at PCSX source code? It's really good emu and its source code is easy to read.
BTW I'm not telling that PCSX is that easy, I'm just saying that you should read it, because ePSXe's source code is not available, but you should be prepare for A LOT of study, in order to study with PCSX beforehand, good luck!
