In the Containers card of the bag form (visible once the bag type has been saved at least once):

1. Pick a container in the dropdown (only containers whose Usage is Bag only or Both and that are active are offered), enter the Qty and choose whether it is per Bag or per Meal, then click Add. The row appears in the table.
2. Remove a row with the red × button.
3. Click Save Bag Type on the form – container rows are stored when the bag is saved.

Use Copy from bag type to import another bag's container list. The assigned list is snapshotted onto each order's bags for packing lists.