Thank you to misinformation for the informative post.
As a head coach who has hired many assistants the process works differently based on where you are. Some states have different regulations, and every institution has their own policies. If I knew who I wanted I simply posted the job on the university website and within seven days could then bring in candidates. If it was late in the summer some times HR let me simply hire who I wanted. Every situation is different. But what I will say to all the young coaches looking for jobs. I know of no head coach who hasn't kept a list of potential assistant coaches. It IS about networking. One of the candidates for my assistant position did not get hired. But he kept in touch with me on a consistent basis, and I watched how he developed at the place he was coaching. The next time I had an opening, I hired him. So to all the younger people, get to know the college coaches, do what you can to stay in touch with them, and then when its your turn do a great job.