We require you to upload one multiple page PDF file with the pages in numerical order to be able to create the spreads accordingly. The multiple page PDF file should have the individual pages(not spreads) in this order:
Front Cover is the first page, inside of the front cover is Page2, Page3, Page4, ... the last page is the Back Cover.
Or you can upload a zip(compressed) folder with all your files within the folder. Please make sure the files in the folder are named after their corresponding pages(not spreads).
Page1 Front Cover.pdf, Page2.pdf, Page3.pdf, Page4.pdf, ...Page12 Back Cover.pdf
Download a file compression program.