Good for you!
A few thoughts that come to mind....
Feel free to tell folks including the judges that you are brand new to the game. In my experience people will often be willing to help you out as a newbie.
You'll be braced with one other dog and handler. No shock collars are allowed. You'll need a blank gun. The judges often are on horses. Courses vary but often you'll start out in a field with no birds planted to give the dogs a chance to stretch out and handle a bit before entering the field with planted birds.
If your dog (a weim?) has some basic handling knowledge and responds to your commands to turn or come to you, feel free to use them. A dog that works with you will hunt with and for you--one of the things the judges are looking for. However (and this goes for most of the test) if you are unsure your dog will comply with commands, unless it's running right off the course or getting in the way of the other dog and handler, it's better to keep your mouth shut than demonstrate to the judges that your dog won't comply with a command.
Scope out your course as you move along. In the bird field, bird planters usually will plant birds near identifiable cover--a tree or group of shrubs in the field, a patch of better grass, along an edge where short grass runs into dense/tall grass--etc. If you can "steer" your dog while it's running and it hasn't found a bird after a bit, feel free to direct it to likely looking spots.
The pointing requirements are pretty low for JH, but your dog will need to demonstrate it recognizes bird scent and pauses briefly--doesn't have to be for long or a classic point...but it will need to find and briefly point a bird or two to do well under most judges. If it points a bird well, move around and approach it from the front rather than come from behind it or to the side to flush the bird. After the flush and while the dog is very interested in the bird (might even be chasing it) fire the blank gun. They'll need to demonstrate no problems with the gun as well. Even though it's a blank gun, watch where you are in relation to judges and horse when shooting the gun.
Sometimes with the young dogs that run JH this can be a problem.If you observe your dog chasing or playing with the other dog in the brace--or vice versa--try to pull it to a different area of the field to avoid contact. Also try not to allow your dog to mess up a bird being worked by the other dog if possible, especially if that dog hasn't worked a bird well yet.
And try to relax and approach it as a learning experience and simple fun!
Good luck!