Adding Field in New SO Form

Hello, i have this scenario where I want to add a existing field, from another form to the NEW SalesOrder Form

here is the New Sales Order Form / Create Sales Order ( Sales and marketing/Common/Sales orders/All sales orders (NEW SO))

I want to add a field(ComboBox) in that Form, a field from the Header View of the created SO, here's the Form:

I want to Add the Employee(ComboBox) in the Create SO Form, so it will be easy to edit and add a Employee Dimension.

The output should be like this:

can you help me achieve that output? thanks.