A battery manufacturer wants to sell their batteries in boxes of 12 and cases of...

 In Dynamics 365 Sales, when setting up a unit group, you must first define the base unit. This is the fundamental unit of measurement for a product and serves as the foundation for defining related units within the group.

 For the battery manufacturer, defining a base unit (such as a single battery) is necessary before configuring related units for boxes of 12 and cases of 24 boxes, as these will be multiples or related units derived from the base unit.