I would suggest:

  1. buy book "Learning Perl" by Randal Schwartz and Tom
     Christiansen - I believe there's a 3rd edition now.  It's
     an excellent primer, and it has a whole chapter on CGI
     programming.

  2. I did

         perldoc -q cgi

     and came up with this section:

               Where can I learn about CGI or Web programming in Perl?

               For modules, get the CGI or LWP modules from CPAN.  For
+ text‐
               books, see the two especially dedicated to web stuff in
+ the
               question on books.  For problems and questions related 
+to the
               web, like ‘‘Why do I get 500 Errors’’ or ‘‘Why doesn’t 
+it run
               from the browser right when it runs fine on the command
+ line’’,
               see the troubleshooting guides and references in perlfa
+q9 or in
               the CGI MetaFAQ:

                       http://www.perl.org/CGI_MetaFAQ.html
[download]

Also, I'd go to www.perl.com - look there. And go to google and search for "perl cgi tutorial" or something similar. HTH.