Update "Link to another field" based on same text

Ultimate goal: Have analytics in one place so I can run graphs/reports.

I have a spreadsheet where folks have been entering analytics. I also have a table with the stories. I’d like to merge them in some way. One idea i had was to create a new table for the FB posts. Table “FB Posts” column “FB Text” includes the same text as Table “Editorial Content” Column “Social Text”. I added a Lookup column to Editorial content so it will show the FB reach, but I need to fill out the “Link to FB Posts table” to make the lookup column work.

I thought I could run an automation. Here’s what I have so far:

Trigger when record enters a view in “FB Posts” (I added a checkbox in FB posts table to trigger this).
Find records
Table Editorial Content
Find records based on Condition where “Social Text” contains "Record (Step 1: Trigger) Field Values “FB Text”

But I get lost at the Update Action. Thanks for your help!