Add a Sales Order to a service order when it was created. How to setup look a like picture

Hi @hoatran1109 
At the moment the system only allows to create new Service Orders from Sales Order. There is no option of linking an existing Service Order to a Sales Order.

To create a new Service Order from a Sales Order, on the Sales Order, for the lines you want to schedule, on the Details tab, set Require Appointment checkbox to true, then use action of Create Service Order.

Let me know if this answers your question