Hi Alexis,

With standard mugs (not panorama mugs), it works in the same way as with other products with multiple print areas:
1. Upload the desired designs individually,
2. Click on Upload again in the design window,
3. Click on Select Designs to select the two already uploaded
4. Add the mug as a product and arrange the designs on the print areas.

For more information you can also check out our Forum.

Best regards,
Sandra