There are various articles explaining how to create a Product or Item but what exactly is the difference?
Products are above depots, whereas items are depot specific.
Products cannot be added to transactions but items can.
Looking at the below image, in order to buy or sell product "Brick Rustic", an item needs to be created per depot (ERP Go only allows 1 item per depot). When therefore buying or selling bricks, the On hand Qty reflects against the item.
Because Products are above depots, it stands to reason why stock levels would be configured per depot under the Product Location tab:
