...
The Specification column is available if the Use Sets for Sales option is selected on the Administration > Settings > Purchasing and Warehouses form, and you can select a specification to be used for the item if item is a Set. Click the Set Components button on the toolbar to specify the components for the set.
...
You can use the Income Item, Expense Item, and Business Activity columns to specify parameters for further analysis of the sales transaction.
The values in the Amount column are automatically calculated for each item according to the specified price, quantity, and discount.
...