Soccer Association for Youth, USA

In my experience, there wasn't really an interview process, just a sign-up for interested workers. After signing up, all potential referees had to take a 6-week course, culminating in a test that had a specific score requirement.

Working the games is pretty straight-forward. You need to show up about 20 minutes before the games start and perform a field inspection. Then, you speak to the coaches on each side, then to all of the players, and then the game is underway.