As always, I'm reluctant to help out people who won't do themselves the service of reading for a few minutes before jabbing themselves with a pin

...But, since you obviously have little research and information on steroids in general, I'll do you a favor and point you towards testosterone propionate as a good first step. Check out the steroid profiles available on this site for more information!
Testosterone Propionate is simply the testosterone hormone attached to an ester that regulates it's release very quickly. It's taken every two days, so it starts to kick in fast, but more importantly, you can get it out of you quickly if there's a problem. For your first cycle, do a nice moderate propionate only cycle and keep a bottle of nolvadex/clomid on hand for post cycle therapy (use search feature in forums).