I personally wouldn't run the SARMs. I would jump straight to testosterone with what I know now. SARMs still have too many unknowns and not a single SARM has ever been FDA approved for use and only very limited human trials have been done on maybe one or two. Almost all studies to date are rat studies.
you dont... s23 is the most suppressive sarm there is, even more suppressive than some steroids out there.. the difference is that its far easier to recover from but at your age, you should not be using anything like s23.. watch my video on the sarms with the most suppression as well as the sarms with the least amount of suppression...