Gaining muscle

Okay, well I workout at home with a bowflex, and just ran out of a protein shake called Muscle Milk (Whey Protein). My friends have been telling me about Creatine, what exactly does that do? They also told me if I want to gain really nice muscle then I...

should use something called Nitro-Tech, which contains creatine. They told me that it fills your muscles with water, and if you don't drink enough water during the day then you can have liver problems, is that true? I'm already in good shape, I got muscle, not as much as my friends b/c they use this Nitro-Tech stuff. Will this and a Bowflex give me the results I want?

It depends on your body, what works for someone else might not work for you. You could give it a shot though and see how you like it.