First thing is inserting the images and patterns that you want. If you need a refresher on how to do this, be sure to check out my Part 1 post!
Next, layer up the images the way you want and click and drag your mouse to select all of the images.
After you select all of the pictures, several options that were previously grayed out on the right hand side will become available. One of those is "slice" and that's where we're headed! Give it a click.