Every year there seems to be a lot of confusion over the car camping situation at Coachella. Not everything is explained as clearly as it could be.
Your spot will be 10 ft x 30 ft. You can’t occupy a car camping spot without a car parked there. There’s no limit to how many people are allowed in one campsite, but I’d say that 3 tents is the most that you’d be able to fit, and that’s pushing it.
I’m not going to go over all of the specifics, but here are some photos I took at Coachella in 2011 that should give you an idea of what the car camping setup is like.
Here’s a view of the front of a line of cars in the designated car camping area. You park your car and set up your stuff behind it. Then, behind your stuff, someone sets up their stuff, and then their car is parked behind that. This constitutes a row. There’s a whole bunch of these.
Here’s an unrelated image of me losing in beer pong.
That’s all I’ve got. I hope this was helpful!