I used multiple kits from 2 designers, et-designs and Emento Designs that I had in my stash.
I created my own curled edge to the top paper and clipped in a third paper to look like the backside of the top paper.
To get the 'curl' I used the dodge and burn tool to emphasize the highlights and shadows. To get just the right shadow under the curl I again used the burn tool at a low opacity.
From there it was just a matter of tucking elements behind and in front of the top paper and the curl.