You can download samples  below and or download and edit psd source files using smart object here then upload to test the app.

You can use any design and upload to any mockup on the same category, so that you can create UNLIMITED 3D graphic design layouts.

We are adding more layouts on weekly basis, if you find some attractive 3D book cover layouts that we don't have, just send us those images, we will put them on to-do list immediately to make sure this is the largest 3D mockup resources in the world.