On the bag type form, the Containers panel lists what is packed in this bag. Pick a container from Select container..., enter a Qty and choose Per - Per Bag (fixed count per bag) or Per Meal (multiplied by the meals in the bag) - and click add. Drag rows to reorder; use the trash icon to remove. Use Copy from bag type to import another bag type's container list (existing rows are kept, duplicates skipped). Everything is saved when you click Save on the bag type. Only active containers with usage Bag only or Both are offered; the list flags any container that has since been made inactive.