Fronts: Upload the front card designs altogether as either a multi-page file or, we suggest adding them all to a zip folder.
Back: Upload separately using the "Add More Files" button
One Deck: alternatively, you can submit your file as a single PDF file (otherwise known as a One Deck file), whereby the file is compiled ad: Front, Back, Front, Back etc.
If you'd prefer to send artwork later or have a larger file (50MB+) select "Skip Upload"