On an order, a work order template can be assigned to the order lines (line by line manually) 

Standard procedure

1.	Go to Rental order management > Rental orders > All rental orders.
2.	In the list, click the rental order link in the selected row.
3.	Expand the Line details section.
4.	Click the Rental tab.
5.	In the Work order template ID field, enter or select a value.
6.	Click Save.