I'm having trouble adding a variation to my existing listing (we're the owner of the brand, and the listing doesn't have existing variations yet).

I've tried using the Edit Listing page first, but I was unable to add any images for the variant. (Looking through the forums suggested that size variants don't allow new images, but I'm forced to select both "size" and "flavour" variant types to enter the Add Variant page)

When I contacted Amazon Support, they suggested using an Inventory File to add the variant, but there's no instructions on *how* to set up the file before submitting. I've tried checking the Help page, however it only covers either creating a new product listing with variants, or adding to an ASIN that *already* has variants.

What should we do in this case? Should I go ahead with the create variants page anyways and try adding the images manually afterwards? Or should I duplicate the existing listing, change the contents to match the variant, then try merging them using the Inventory File?