Linking several records to a single record in another table

[ChrisG]

I have a situation where:

1) I use a template to create several records in "Table A". 

2) I link those records to a singular record in "Table B" on creation.

I have tried using an automation that checks when the record is created in "Table A", finds the record in "Table B" and links the record from "Table A" to the record found. Tests for individual records work (when I am testing the automation): however, it does not work when I try with the template. 

I have also tried using a checkbox that populates the chosen record in "Table B" with the respective records in "Table A" by looping through the designated records in "Table A" and then linking them seperately to the chosen record in "Table B".  

Both of these methods have not been working for me. Any suggestions?

[ChrisG]

I currently only have the free "PRO trial" so I do not think I have access to it. The base is under a workspace with the pro trial and I am trying to add a scripting step. Custom extensions work for me and I am able to link a button to activate it.

[Alyssa_Buchthal]

The custom extension will be great! Just a bit of a steeper learning curve if you're not familiar with javascript. Be careful as you will lose it once the trial is over if you don't upgrade permanently. 

[ChrisG]

How do I connect the extension to an automation? I already have scripts that I run on activation as well as scripts that are activated with a button, but I am unsure how to connect it with an automation or have it mimic the same behavior.

[Alyssa_Buchthal]

Extensions aren't meant to interact with automations. You can set the extension to run with a variety of triggers though. Guessing you already found it, but this link will give you an overview of the available input types.

[ChrisG]

Are the avaliable input types for when the script already begins running (awaits input from user) or is it to activate the script (before it is ran)? Correct me if I am wrong, but I am trying to run it without having to even run the script but the input types are not triggers to run the script. 

The run a script action that the above image recommends is the "run a script" step in automations which is outside of my plan's scope.