How long have you been training and what is your diet like now? If you haven't been training long get a good bulking (clean) diet, a good multi, drink plenty of water and train heavy with simple excercises (squat, deads, bench, presses ets...) I would say do that for at least a year. See what your body can do on it's own first. If you are going to compete and you want to suppliment read, read, read, read and then read more. Everybody responds differently, your body may not do what someone elses does so while you are training eating and supplimenting take pictures and journal so you can track what works and what doesn't. If you are not going to compete I would stay away from the stuff but just my two cents.
I would also suggest not taking anything if you don't already have kids and want some...again just my opinion.
Good luck and be safe.