Welcome to the community, @Grace_Hui!
Unfortunately, Airtable’s “Find Records” action doesn’t work in the way that most of us expected it to work, because it won’t loop through the found records. It simply returns a text array of Record ID’s. Therefore, you can’t achieve the result that you’re looking for in this way.
I would highly recommend sending an email to email@example.com to ask them to please improve how their “Find Records” action works. They don’t often listen to customer requests, but who knows — if we can get enough people emailing them about this issue, it’s possible that they might fix this behavior.
(On a side note, Make.com ALWAYS loops through the found records in Airtable to let you quickly & easily send personalized emails, so I usually create these sorts of automations in Make.)
However, if you keep this automation within Airtable, you would need to figure out a way to trigger each record individually, instead of in bulk.
Otherwise, a clever trick to make this happen would be to have your automation paste the resulting text array of Record ID’s into a linked record field that lives in ANOTHER TABLE that exists simply for the purpose of this automation. (This linked record field would link back to your original table.) You can paste into any record in this table, or just create an empty record to paste into.
By pasting the text array of Record ID’s into that linked record field, you have then ALSO updated each & every one of those records in the original table. (To be more specific, you have actually updated the linked record field for each one of those records.)
Then, you can setup a 2nd automation that watches for the original table’s linked record field to get updated.
This 2nd automation will trigger for each record individually (one record at a time), so you can send your personalized emails from this 2nd automation.