First off, your question is very general so forgive my rather general response.

Assuming you have standard perl knowledge, the first thing to do it check out Ovid's CGI course. This will give you a good idea of how CGI works and get you started with basics.

Secondly you'll need a database module, ala DBI. Oreilly has a good book on DBI ISBN 1565926994

Hope these things make some good sense to you.