for what its worth, the process outlined does works, i tried it. part of it is metabolism and body type, though. not everyone will gain as much. and not everyone will really want this type of muscle. its bulky and slow, not the best for more dynamic athletes. you can alter the routine to build more lean muscle, though, and it works the same way. you just won't be able to say you put on some huge number of lbs in muscle.
p.s. - don't use supplements and such. they're bad for you.
note - i'm not an expert and this is based on my personal research. its worked for me, though. i actually decreased in size but maintained strength after switching from one style to another.
Also, could you be more specific about detrimental supplements?
i highly recommend avoiding vitamins, supplements, powders, and such as much as possible. its easy to overdo them, and they will start to harm your liver. if you can find some sort of natural protein source powder, that would probably be cool. for context, i know someone who is in a coma after liver failure brought on through supplement usage.