Backbar is focused on simplicity and one of the most complex and tedious processes with other inventory software is that they require you to assign items to specific locations. You then have to remember to transfer items to other locations whenever they move (which 95% of people never do, because who has time to do that during a busy service).
Instead, Backbar allows you to setup locations and sublocations, for the purpose of doing your physical inventory counts. All items in your inventory list will show in all of your locations when taking inventory (similar to how most inventory spreadsheets work). If an item is not present in a location, just skip it.
When you view your inventory session reports, items that are skipped will not show any counts for those locations where they don't exist.