Congrats! Champs is like a normal show, just bigger and more fun, and with a few extra rules. Make sure you look at the Member Guide to understand what those are. A few big ones: no whips during championship tests, no readers during championship tests, only one rider per horse at championships, only the competing rider can ride the horse during the show (no trainer warm-ups, etc.), once the horse arrives it has to stay on the grounds (no shipping back and forth from home every day).
Some people will qualify in four classes - two consecutive levels and two consecutive freestyle levels. Those people will be busy. Anyone who qualifies in a regular level is eligible to enter the equitation finals as well.
Others will focus on one test - riding it the day before in a warm-up class, and then riding it in the championship class on the second day.
Others will try to get qualifying scores for the next year in addition to showing in their championship class.
This year I’ll bring one horse, and show in two consecutive level championship classes. I won’t do a warm-up test because he’s doing the upper levels and needs to conserve his energy for when it matters.