...
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.
The tab toolbar buttons
Use the Up and Down (
) buttons to rearrange the items in the list.The Set Components button on the table toolbar is available if the Use Sets for Sales option is selected on the Administration > Settings > Purchasing and Warehouses form). This button is enabled only for items of the Set type (for details, see Items). For each item which is a set, you can select the Specification. To view a list of the set components, click the Set Components button on the toolbar – this opens the Set Components dialog box (below in the topic).
The Set Components dialog box
You can use this dialog box to select the specification for an item which is a set.
...