Apply to Game Central to become a citizen.
By applying to become a game citizen now you will be able to immediately being adventures when you arrive at the festival. Go to Game Central to get your name ticked off the list and to recieve your life card. From there you will go to your chosen faction to begin.
More information about factions, characters and backstory is available in the Game Wiki.
Choosing your faction early gives you time to get an amazing costume together. Having a great costume is a lot of fun. If you want to wait until you arrive to choose a faction make sure you bring a dress up box with you to the festival. Actually a good idea regardless.
Special note: The Onabots this year are in league with the Evilord.