Check-in Check-out inventory help

I am looking for help/tutorial with setting up a check-in/check-out system in Base. I would like to have a check box (Boolean yes/no?) that indicates if an item is in stock… then I want that check box to add or subtract from the item quantity. I can give each item its own line in the table and just use the “checked in” status as a quantity of 1, but then it would need to roll up all like items for a quantity total… or is there a better way to check out an item and adjust the quantity, even if there are multiples? Help!

https://documentation.libreoffice.org/en/english-documentation/

SimpleInventory_embedded.odb (52.2 KB)