To do this task
Decide which unit of measure mode is right for your business.
Click Single U/M Per Item or Multiple U/M Per Item.
(Optional) If you don't want to define a unit of measure right now and assign it to the current item, click to clear the Begin defining units of measure checkbox.
Note: This checkbox is available only if you were in the New Item or Edit Item window when you clicked the Enable button. If you started in the Preferences window, you can assign a unit of measure when you create or edit an item or when you add an item to a transaction.
If the Begin defining units of measure checkbox is selected, click Next and complete the wizard.