From where did you download the mockup, from Zazzle, or from another site? Save the mockup as a .png file, then paste your image as a layer, above the mockup layer.
then keep reading-- https://community.zazzle.com/t5/store-management/how-to-create-a-simple-mockup/m-p/36662 KeegansCreations said: Take advantage of the new Download Mockup feature that lets you download Zazzle's mockup images. It's under More Options on the product page. Then use your graphics program to cut away the background so you can put the product images on your banner background.
