Registration lasts about an hour. There is no reason to be there right at the start of registration. After registration, everyone walks the course. This is very important. Some courses are very clear and simple.
Some courses are complicated and confusing.
There are different routes and turns for each division and distance. Make sure you are following the route for your distance. Pay attention to landmarks, turns, and hills. Figure out how to recognize the important features of the course - especially the finish. After the walk through finishes, there is a short break before the races begin.