In order to set up sale items go to Property Management / Item Manager.

1. Open Sale Items tab and click Add Item to create a sale item.

2. Before entering item details you can create Categories into which you can group your sale items.

3. Enter the Item Name and select the category:

4. Then, select the default account for item sales and enter item price. You can enter the price in each of the supported currencies separately or, if you set price in one currency only, it will be converted automatically to other currencies. You can also set up different Price for Staff Members:

5. If you enable the item to be sold on the booking engine, you will be able to access more options:

You can read more about it here: How to add extras and sale items in Booking Engine

6. Select if you want to track inventory for the item and count it during Shift Switches.

7. Save and Close your new sale item.

If you decided to track inventory go to Property Management / Inventory Manager and select the newly created item. Click on Adjust in order to add the Inventory Count: