Well for starters you would only need to use 1 database and it should be SQL. You can of course store data in a txt file or excel but this is not a database, SQL Server is.

You would need at least 2 tables in this database, 1 would hold user info the other would hold class info. You may want a third that links classes to users if needed.

I would suggest that you search online for database programming tutorials or samples to help you get started.