Well, I am teaching Zanath to jump right now as well
It probably helps that both her and I absolutely love jumping, but oh well.
So, we started you with 4 trot poles along the ground, we walked, trotted and cantered over them. It took us a long time to begin cantering over jumps. The I took one pole, and made a 20cm jump, and took the other trot poles away. We went over that, then we slowly kept making it larger for her. As I am inexperienced with horse training, and this is all that I have done, maybe try a trainer once? I dunno, all I have been told is "get a trainer!"