Help needed linking tables

Hi everybody, my first post here. I actually have very little knowledge of JS, I am actually a VB coder. I do however find some aspects of the collection system frustrating. For example, I want to join two tables through a reference where the reference field is owner - but I can’t because I can’t make a system field a primary key (which I find odd as owner seems the obvious filed to use)? I also now discover that I cannot connect a text input to a reference field for write?

Anyway, I settled for user logged in email as my join (not ideal for various reasons but it will do) - but have wasted days going down dead ends. Here is what I want to achieve:

The user currently completes a form and when clicking a button, the values are sent to the pulse collection (all successfully done without any code). I also populate a hidden text field (within the form) with the users email address from my members collection, again simply by doing a data link. I want to take that email address and on the click of the button, also send that value to the pulse collection and insert it into the reference field (so to complete the table join)

So my problems:

1/ As far as I can see, without writing code, you cannot populate a filed with a data link from one table and send to a field in another - so what code do I need to do the insert?
2/ How do you insert data into a reference field?

A huge thank you for any help :slight_smile: