Jumping Green Horse Help?

So I have a horse that is green at jumping and she is most def. not a natural. She is skiddish, and nervous of her footing. She loved to jump but hates the jumps themselves...Im only do itty bitty x-rails with her right now because my trainer said she can move to them but now she's antsy and cat leaps over everything...are there any books anyone has any ideas about i could read or suggestions? because i most def don't want to screw her up doing the wrong method