On the sales screen there are several ways you can sell from a separate store
•You can change to a different Division (Alt+F2) if the different division has a different default store set. See Settings / Divisions
•You can change the store using the Store drop down combo on the main screen and then it will use that store until the next sale or the store is changed again
•You can enter an item and then select ‘Edit’ which will bring up the Edit screen where you can search for the item in other stores and select a different store. Commonly you would set the system to automatically bring up the Edit screen if insufficient stock so you can quickly check the other stores when the current store does not have it in stock.