Link to record in another table based on value


I’m bringing time entries into Airtable. I need to link those records in a time table to records in an existing staff table. Unfortunately, the data I receive from the time tracking system only lists a user ID, not a human readable name.

So, I added that userID as a field in my staff table hoping I could then use that to match and link. But, I haven’t figured out how to actually do this. Any ideas?