How to compare 2 excel files

Not sure how to do this, any suggestions?
I have 2 excel files:
file A
badge #
name
position

file B
F/N
L/N
course name
course date

Thought I could use access to do this, I need to look up the badge # in file A, a user was qeuerying the last name one at a time (are hundreds, which get uploaded into another db)
I created an expression to combine F/N & L/N into another field, not sure how to "compare" them; I created pk/fk which maybe part of the problem why this isn't working? Any ideas?

what is the link between the two files? The names are not corresponding.

You can use Access to link both spreadsheets as tables in Access. Doing so you can run a query on the tables by linking them. To do that you need a field to link both tables.

HTH