Autopopulate subform field based on lookup field in that subform

Autopopulate subform field based on lookup field in that subform

Hello. Im trying to make quotation app in the creator. I know very little about coding so I code based on what I find in the web. I cant figure this one out tho.

I created a form with which I add my services to the list. Each service has its name, cost, value format and description.



Name is important for the employee - needs to be short, contain only the most important information
Description is important for the client - needs to understand exactly what is offered

In the PDF template that is created for the client, only description needs to be included. In qutation form I pick the name of the client that Im creating quotation for and then add services that he is intrested in. Im picking them by name. I want the description to be autofilled in the form:
I managed to create a workflow that autopopulates the email and other important for me data, based on my "Klient" pick.

Now I need to create a workflow that will autopopulate "Opis" (description) based on the name of the service I picked.
  1. if(row.listaproduktow == null)
  2. {
  3. row.opisdowyceny="";
  4. }
  5. else
  6. {
  7. rec = listaproduktow[ID == input.Elementy_wyceny];
  8. row.opisdowyceny=rec.Opis;
  9. }

This is what I started with but while its correct and has no errors, it does nothing to my form so I guess its totally wrong.

Anyone? Thanks!