reattaching a bicycle brake

Since 2001, over 90,000 cyclist's have joined Cycling Forums to discuss topics from general cycling to equipment, training, racing and travel or vacation destinations (especially in europe during the tour de france). We also feature an great deals in our online store, 100's of articles, classifieds and product reviews.

ok so my bike is a HUFFY mountain bike now i'm not sure what happened exactly (it was a while ago) or how to fix it but i only have one bike brack and that brake is under my left hand...under my right is a lax handle with no tension or anything cause the break is gone....for some reason it's in a bag in my room....and i don't know how to put it back...i was probably trying to make the brakes tighter or something like a year or so ago and didn't realize that i hadn't yet taken bike repair 101 so anyway....if it's not too much trouble or if you need more info or whatever...could u help me fix this

thanks:p