Ajadea:

The nurse absentmindedly responds to your question as she processes your purchase. "At the Ranger's Station, at the edge of town. Can't miss it- there'll be plenty of trainers going there today."
Heading to the Ranger's station, you find it almost as hectic as the pokemon center; there's a line going out the door. As soon as you get to the counter, you pay your fee, and the woman there hands you a form to fill out- basic stuff, name, trainer number, what pokemon you'll be bringing with you, etc. There's also a few disclaimers to fill out- first, a non-liability waiver, and the second detailing the magnemite-cam that'll be following you. Your time in the competition will be stored online, and potentially on TV, and if the magnemite-cam is destroyed you will immediately have to forfeit the competition- to prevent cheating, of course. It should be tough, and it knows to stay out of the way, but it's something to consider. Tampering with the cam is also a disqualifying offense.
Finally, the day of the competition you choose to enter- Tuesday or Thursday. The first day is on Tuesday, and then the next day the Rangers go in and try to fix things up, bring it back to a natural state, then on Thursday the next batch goes in. Do note that if there is an imbalance, you may be rolled into a different day.
Finally, once you turn in the form, you're given a premier ball with Moira- CLVII engraved on it.