How long does it take to assemble a staff?

I realize that you do not hire people overnight. There is a procedure that has to be followed and those things take time. But how much time? I would assume that when a coach makes the final cut, he is beginning to think who he wants on his staff if he gets the job, so he has that much already done. And perhaps has even made a few private inquiries. On his initial staff he probably is not going to hire someone he does not know. So how long should it take?