First of all, I would suggest you to avoid using Behringer equipment since it sucks.
Now - assuming you have that mixer specific mixer.
SC OUT -> LINE IN (any of the stereo inputs 5-12)
SC IN -> MAIN OUT
CTRL ROOM OUT -> Monitors
Guitars -> Guitar Amp -> Any of the mono line ins, or if no amp - to the mic ins.
That's how I'd do it, just by looking at it. Dunno how it works really so there maybe a better way to do it.
Use TRS cables (1/4 jacks with 2 rings, like stereo jacks) for balanced (and noiseless) sound.