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.