First, I'm not SuperMod (but then, who is, right?), but step #1 is disconnect the battery, yeah?
Haven't looked under there in a while but from memory..
After removing the fusebox cover, look down onto the face where the fuses and relays are and you'll see two bolts, small-ish, maybe 8mm?
Those are really lo-o-ng bolts, but remove them and the entire box will lift right up.
You'll see then how the harness(s) plug in underneath, as long as you're not brutal with it you really can't hurt anything.
At a glance from there you'll figure it out.