You have to be genetically sensitive to steroids and to a degree you need proper muscle attachments.
There are top bodybuilders however who are quite ugly and have ugly physiques. They are huge though which is the ultimate requirement.
You need discipline to live the restrictive lifestyle of eating, drugging, dieting.
But generally speaking, you just take huge amounts of drugs, eat a lot, an train with common sense.
So, in the final analysis, you need to be willing to risk your health for your muscles.