Settings > Delivery Settings > Containers (/admin/containertypes) defines the physical containers your kitchen packs: meal trays, sauce cups, ice packs, etc. For each container enter a Name, choose Usage - Bag only (packed into bags), Meal only (assigned to meal portions) or Both - and, for meal containers, a Slot Size: how many standard meal slots it uses in a bag (default 1.0; e.g. 1.67 when a bag that holds 5 standard trays holds only 3 of these). Use the Active toggle in the More menu to retire a container; inactive ones stay on existing assignments but no longer appear in dropdowns (a warning tells you how many bag types still use it).

The list shows ID, Name, Type, Slot Size and Used By (number of bag types), split into active and inactive tables.