Rapid 6x9 KDP Cover Formatting

I already have my full-color cover laid out in a single PDF; it only needs to be resized and placed on the correct KDP template for a 6" × 9" paperback with a 144-page spine. Amazon will add the barcode, so no placeholder is necessary... (Budget: $10 - $30 USD, Jobs: Adobe Acrobat, Adobe InDesign, Book Cover Design, Brochure Design, Design Optimization, Graphic Design, Photoshop, Print Design, Publishing, Typography)