Circuit board manufacturers use reference designators indicate component location coordinates on the job traveler.  This can be achieved within the BOM by attaching multiple References to a component that print on the job traveler.  

Each reference consists of two fields.  The Reference can be a location coordinate or drawing reference or it can be used for any table that has a one-to-many relationship with the component.  The Qty is optional and represents the quantity relative to one unit of the BOM parent.

NOTE: Component references can be imported using the File – Data Import – BOM – BOM References screen.  

Freeform Job Notes can be entered against any component and provide an informal alternative to using References.