You usually select a work center with the category, "production line" in the PP System. For this work center category, the standard values Requirements, Set up, and Tear down are already set.

If you select another work center category, you must make sure that you enter a standard value key that allows the standard values Requirements, Set up, and Tear down.
You can map the structure of the production line in the system by creating a line hierarchy.

If you use the same standard value key for all the work centers on the line, the system copies the descriptions of the standard values into the routing, as column headings in the operation overview.
If you use different standard value keys for the work centers, the system copies the descriptions into the routing that is entered in the control data for the routing in Customizing.