Open /admin/productcategories (also reachable from the Products Dashboard Create New > Category) and click Add new. Fields: Name (required; first letter is capitalised), Order, Description, BgColor, Text-color, Tag (Unique ID - no Spaces), and toggles: Show on website? ("Users can see and filter this category when selecting extras"), Show as Anchor on Products (anchor navigation on the Products page, shown only when Show on website? is on), Show as Anchor on Extras (anchor navigation on the Extras page), and Show in POS Terminal? (visible to employees). Save, then assign the category on each extra or product via Product Categories. The list shows the Show on website / Show on Anchor / Show in POS Terminal status and supports drag-and-drop ordering.