can someone tell me exactly how a 531 routine works? ive been searching and asking around and it seems that there is a different answer every time.

3 sets of 5 reps, then a seconday and mabey even a 3rd exercise for each body part i do? how many reps and sets of these other exercises do i do?

next week down to 3 sets of 3 reps with more weight? what about a 2nd and 3rd exercise? 4th?

any help would be great, thanks alot guys.