When your horse is first learning to jump, it is important to design simple jumps, and then a simple course, so that it develops confidence. Your horse needs to learn where to put its feet and how to gauge distances -- the point at which it takes off to get adequate clearance over the jump.
Set up ground poles 2.7 m (9 feet) apart, or twice your horse's trot stride. Laura Whitfield, trainer and owner of Poseidon Sport Horses of Hutto, Texas, says that your horse should be able to balance through five or six of these poles on a relaxed rein. Then, you can move the poles 4.5 m (15 feet) apart -- or far enough to allow for one canter stride.
Set up a small crossrail that is no bigger than 45 cm (18 inches) high in the middle. A crossrail is a jump in the shape of an "X" set between two jump standards. Ask your horse to jump this first at the walk, and then at the trot. Once it can do this confidently, raise the crossrail to 60 cm (2 feet) in the middle.
Make the jump a 60 cm (2 foot) vertical, or fence, and trot your horse over it. Ask him to canter after landing. When your horse is comfortable with that 60 cm (2 foot) fence, place a few similar fences at various spots around the arena for your horse to jump. Continue to ask your horse to canter after landing the jump, but bring it back to the trot when approaching the next fence.
Set up a jumping grid. Whitfield reminds riders and trainers that young horses especially do not have a balanced canter to make it down long lines, so doing gridwork is helpful for them. Set up a trot pole 2.7 m (9 feet) in front of a 60 cm (2 foot) crossrail with a 60 cm (2 foot) vertical about 9 m (30 feet) from the crossrail. Once your horse is comfortable with this, make the second jump an oxer -- which is two fences put directly next to each other or a wider jump -- or expand the grid to include a larger vertical.
Create a small course with no more than three to four strides between each jump or line. Your horse will likely have a very forward canter so assume a longer stride rather than interfere too much with your horse before each jump. At this stage, no fence should be smaller than 75 cm (2 feet, 6 inches). Based on a horse's average 3.6 m (12 foot) stride, a three-stride line should be about 1.2 m (48 inches); four strides 1.5 m (60 inches); and five strides 1.8 m (72 inches). You may have to adjust this in the early stages until you become more familiar with your horse's stride. Start by asking your horse to trot into the first jump, cantering out. Once it is relaxed and rhythmic, canter the whole course.
When setting the ground poles at Step 1, start with just one pole and then add according to your horse's confidence. When you start gridwork with the crossrail and vertical, set a "placing pole" between the two jumps if the horse is trying to rush through the space between the two jumps; this forces it to focus. It is always good to warm up trotting a fence, as it forces your horse to rock back on its hind end. It takes practice for a novice rider to trot over a fence well, without interfering with your horse, so it is good practice for the rider as well.
Once your horse is ready to jump a course, do not make any fence smaller than 75 cm (2 feet, 6 inches) -- your horse will learn to jump sloppily if it spends too much time on small fences. At this point in its training, your horse can either jump or not. A fence that is 75 cm (2 feet, 6 inches) is really only a large canter stride for a 16-hand horse.