Odbc table join or calculated fields in ms query excel

Hello All,
I'm new to database management but I have DB1 and DB2 through an Open database connection.

I want to create a join between the two tables through MS query so that I can create a unique ID.
DB1 has a full name field. DB2 has 3 fields:{first_name, Last_name, user ID}

Ultimately I want to use the user ID.

Please advise on how I should proceed or point me in the right direction if you're familiar with the scenario.

Thank you.

MP