How to choose jersey numbers for basketball players?

I’m doing a project which includes choosing basketball players and their salaries. I need to pick their jersey numbers, but I don’t know how. I’m not really good at basketball, prescription drugs so does it matter what number goes out to who?
I am choosing real players from already existing basketball teams, that’s what I’m suppose to do. I’m also changing their salaries, and I don’t know what I should do about the numbers because if I keep their old jersey numbers there might be two players with the same one.