Prep your mockup.
In Photoshop, prepare your pattern so it can be applied to a product mockup. To start, create a new file (File > New). Set the Width and Height to 596x479 pixels, the Resolution to 150 pixels/inch, and click Create. Open the Libraries panel and select the UNWRP Patterns library.
Drag your new pattern from the library to the artboard and press Enter or Return to place it. Use Control+A (Windows) or Command+A (macOS) to select the pattern, choose Edit > Define Pattern, rename it, and click OK.