Using Box "create a sign request," signature fields not presented to recipient

Goal:
Seeking to use the Box “Create a sign request” integration, but signature fields not presented to recipient.

Overview
I’m able to successfully use the box “Create a sign request” API directly, with python. Now I’m trying to set up the make.com integration so that non-programmers can use it.

In box-speak, I want to be using a signature template document so that the signature request is presented with the signature fields positioned and ready to sign. In the make UI, I’ve tried combinations of using the Source parameter and Template parameter without success. It’s not clear how these map to the underlying Box API.

Any help from someone who has already debugged this will be most appreciated.
make-dialog-3