Go through every Main thread discussing each steroid, and you will see how people percieve them. after that, look into first cycle logs, and read some long term cycle logs,
@Slowww has an especially detailed log and proven results.
After that, read one of the billion compond discussion that pop up again and again (Is primo better than EQ? should you take Tbol? Is Dbol good? what does Anadrol do to your appetite as an oral vs and injectable, what peptides did the most for you, what is the perfect bulking stack,etc.)
Study for medical school if you are in a country that has exams to get into med school and some of your friends are studying for it. or at least read some medical journals, medical guidelines/national association Journals for each specialty (nephrology, cardiovascular, internal medicine, etc.) if you if you are in EU.
Once you are ready, around 21-22yo, I would suggest looking into homebrewing threads. those can save you a shitton of money (or cost you thousands, lmao)