Once you have added multiple store locations and enabled the option for inventory tracking, each product will have new options where you can manage the inventory per location, rather than managing the inventory per product or per variable.
Along with managing inventory per location, you can manage orders per every location added.
When a customer completes an order from a store location, that inventory will be managed from that specified location.
After the product has been shipped, the product stock on that location will be automatically reduced.
If you want to learn more about orders, refer to the Orders page.