The “Find Records” action currently cannot be limited to just the first record. 

I sell automation helper scripts that includes a script that will identify and output the first record ID from a “find records” action. You can then use that record ID in future actions.

If you need record values from that first record, you can create a formula field in the table with the RECORD_ID() function. Then do a second “find record” action based on the record ID.