This is something that differs slightly for each and every horse because horses can be trained differently and respond to leg differently. I would recommend having a couple of lessons with a trainer to insure you are teaching correctly. But with that being said, I know my eq horse was thought by applying inside leg and cueing with outside. It's really important to NOT rely on the reins and bit when teaching. In other words you don't want to "pull" your horse into the other lead. You want to teach from behind. Hope this helps a tad!❤️❤️
Start off over poles, and then no poles and then do them over jumps.
Make sure you don't rush into the lead change.
Keep your horse calm and slow.
When your ready for the change hold inside rein and the outside leg for the way you are changing to.
DO. NOT. DO. ALOT.
If anything do about 2-3 lead changes a week.
If you do it more than that a horse tends to expect them, there for the horse will rush and jump into it and/or they will do lead changes over every jump/pole and while doing circles and basically when you don't even ask for it.
Take a lot of time doing these
I do lots of figure 8s changing from canter to trot and back to canter on the other lead. Then do the same with walk to canter, then do the same halt to canter. Then try ask for the change of lead and they should do a flying change, take your time it may take 1000s of transitions till your horse can but spread the process out if you can and reward him when he listens to you