Groups come from the shared list (edit once, applies everywhere) or belong to this item only. A price adds to the item price; use a negative number for a smaller order.
Pick a group on the left. Changes here apply to every item that uses the group (the list under each group shows which).
Every uploaded plate photo. To put one on an item, open the item in Menu and choose "Upload photo" — or upload here first and pick it from the item's photo menu.
The menu is a single file. Download a copy before big changes, or to edit it in a text editor and upload it back.
Every save keeps a copy. Restoring makes that version live immediately.