Put images into a premade mock up for a brochure.

I purchased a premade mock up (see below). I want to add my brochure into it, and I want the left and right hand pages to conform to the shape of the mock up pages (note that they do not have straight edges due to the lilt of the pages). I am also attaching the layers of the illustrator file. I know that there is a simple way to do this, but I can't find the answer.