Each morning the trail leaders write their planned route on a whiteboard at the registration tent. You find a trail leader going somewhere you're interested in and tell them you'd like to join. They'll gauge your vehicle and experience against the difficulty of the trail. Groups typically cap at 8 trucks, and a leader should have an experienced driver bringing up the rear of the group.
It's an all volunteer event, and this is vacation for everyone. Groups of friends head off without involving anyone else. That's their prerogative of course, and
I was in one of those groups a couple days. Still, it's more fun for newbies and lone attendees if trail groups are formed dynamically.
@RocketCityCrzrs Rory is a superstar in that way.
There's a beginner's run on Monday on the Red Mountain trail.