OM Cloud - How to get the exact attribute name for any field in any order management page?

How to get the exact attribute name for any field in any order management page? What is general process - is there a TRM or something similar that can be referred?

In the current scenario, I am trying to get the exact attribute name for the "Primary Salesperson" field available in Order Line level and also the "Line Type" field. I am trying to write a groovy extension to get both these values for any order line and validate a custom check but seems like I am doing something wrong. Any help on this as well would be very much appreciated.