While "get a trainer" is great advice, I understand that that can be a long, complicated process, and that even with a trainer, there will still be sessions on your horse without your trainer around.
So, in the meantime, a few questions:
1. Have you trained a horse to jump before? How did that go?
a.)Is this YOUR first attempt at jumping as well? Or have you been trained on proper apprach, two-point, timing, etc....
2. Is the confirmation of the horse equiped to handle the stress of jumping? Perhaps this horse is just not physically confident, as well as mentally, to be taking on this tast.
3. How old is this horse?
4. Are you planning on competing - or just having fun at home? I believe this will also make a huge difference on how you train.
a.)If you're just planning on having fun at home, then training will probably come from a whole different view point. Ex: No real NEED for flying lead changes, proper headset, perfect knees, etc...However, all of those things would still be an advantage.