+1 ^^^ Let's go one step at a time and figure out what type of brakes you have. Are they disc (you have a round metal disc that attaches to the hub) or rim brakes (brakes squeeze the rim near the tire)? If you have rim brakes here is a video to help identify what type. You probably have "Linear Pull & V-Brake" or "Cantilever" for a mountain bike but can't say for sure. Once you know the type you can search for more videos if needed on how to adjust/setup and maintain them and if you get stuck just ask here.