If you're new to the jumper ring, you might be worried about memorizing the courses. Jumper classes usually take place in a large ring with at least ten numbered jumps, and the technical nature of the courses means that there will be a lot of different turns to get to those jumps. Thankfully, memorizing a jumper course isn't as difficult as it looks as long as you prepare yourself for it.
First, check the course diagrams in the morning before the first class starts (they will be posted near the in-gate). Look to see if any of the classes are using the same course. If your class shares a course with an earlier class, watch as many riders go as you can in that earlier class. This will put the flow of the course in your mind, help you memorize the striding as you subconsciously keep track of it in each line, and it will show you which options work best for the different horses and riders. You can even walk the course with the riders from the earlier class, but keep in mind that the course designer might tweak the course in between the classes so you might be in for a surprise if you don't walk it again with your own class!
While the course is being set or adjusted for your class, take a good look at the course diagram. Remember where the first jump is so that you will know where to start your walk, as well as where the last jump is so that you don't accidentally end your course walk too early, thinking you have reached the last jump when it fact you have not (it has happened more often than you might think!). As you look at the diagram, get a feel for the flow of the course. Does the course designer tend to use a lot of diagonal lines, broken lines, or rollback turns? Most course designers have their own easily recognizable style, and knowing what that style is will help you to remember what to do in the ring.
When the ring is opened for the walk, go in immediately and start planning your round. Don't forget to think about how you will enter the ring and get to your first jump. Walk the entire course from start to finish, determining how many strides to put in each line and where to turn to each jump. Make sure that you walk every inch of that course, because you will remember the track that you walked when you're in the ring on your horse. Walking each line and turn will help you remember what to do.
Once you've walked the entire course, walk it again (that's why you should start your walk as soon as the ring is open!). This second walk will solidify the track in your mind, making it much easier to remember. It will also give you a chance to test yourself on the striding since you can try to remember the number and then walk it to confirm. If the ring is closed while you're still doing your second walk, don't panic. Leave the ring immediately and then continue that second walk in your mind.
Ensure that you have the first round course clear in your mind before walking the jump-off, and even then, keep the focus mostly on the first round. Look for where to turn, but don't repeat it too many times to yourself or you risk confusing the two rounds. Without that first round, there is no jump-off, and there will be time to go through the jump-off quickly in your head after the bell goes.
Between walking the course and competing, go through the course in your head as many times as you can. Imagine riding each jump in the entire course. If you can go through the whole course in your mind without looking at the real one, you're ready to go.
If you have prepared correctly, the course should come naturally to you once you're on course since you've already been through it so many times that you shouldn't have to think too much about it. The less you have to worry about it, the better you can ride!