To do this task
In the Company section, click Items & Services.
Double-click the item you want to create the unit of measure for.
Note: If you're creating the unit of measure for a new item, click Item at the bottom of the list and then click New. Fill in the item information and then go on to the next step.
In the Unit of Measure section, click the U/M drop-down arrow and click .
Complete the Unit of Measure wizard.
If you need help at any point in the wizard, click Help.