What have I got myself in to? Denver here we come!!

HELP!!!!!!!!!!!!!!!!!
"Wiring the PCM is SUPER easy, it's like a stereo. One constant power, one switched power and one ground and it'll fire up. I spent weeks looking over the diagrams thinking it HAD to be more to it than that. There isn't, provided you have the right wires hooked up and didn't butcher the donor harness."
WHAT WIRES? i've been reading everything and NO ONE has said what wire is +12V all the time and what is Key On +12V!!! I have only the under hood wires, and can't find what to plug hot and switched!