What to Do Once You Get to an SCA Event
The first thing you will want to do when you get to an event is check-in. The check-in area is usually referred to as "Troll" -- think Billy Goat's Gruff and paying tolls.
Troll is where you can pay your site fees, sign any applicable waivers, reserve feast (if still available), get event schedules, class listings, and ask questions. If you have pre-reserved for the event or feast, Troll will have that information.
After going through Troll, change into your garb if you aren't already wearing it.
After that, it's clear sailing. Join in the event, go to the General Populace area, take a class you're interested in, shop Merchant Row, whatever strikes your fancy.