The draft I got some questions help me?

First how does one enter a sports organization draft and can u enter the draft even if you went to a unknown college like if you where div 2 or 3 second what happens to the players who don't get drafted do they get paid last why is the NBA draft such a div 1 draft I mean it's not fair to div 2 or 3 athletes who are really good but don't ever get a shot because they didn't go to the dukes and the north Carolina's also for the players who don't get drafted to international scouts come to them after the draft and offer them contracts to play international