Completely new to this

Hello! Yes, I am totally new to emulators in general, gamecube or otherwise. I think (The key word here is 'think') that using an emulator, in conjunction with a GC game's .iso file, will allow me to play GC games on my PC. Is this true? If so, how do I control them? I have a gamepad, an Xbox 360 controller for windows, but I'm not entirely sure that would work. Besides, it's not like the ingame menus have key assignment options. I've also seen a lot of performance problems. Would 1GB RAM, a 2.8 Ghz processer and an X850 XT Platinum be enough to run these games?
I am trying to figure out how to get Resident Evil 4 up and running, by the way.

Alright, I've got the gist of it thanks to the files in the emulator... But I still have no idea how I'll control the games!