Okay guys and gals, maybe this is a dumb question, but Ill shoot. I just got a really nice Trek 1,0 for a song. Ive always ridden std mtn bikes, never a roadbike. THere are the brake levers at the center, but are those sliver levers up front shifters or brakes- or both? I know the little triggers move the derailleur in 1 direction, but how do I shift it back and forth?