How do I enter my DraftSight Pro upgrade key (24 character) into the Mac version (free download) of DraftSight?  The emailed basic instructions I received indicates I should click the HELP tab at the top of the program and will find a tab to enter the number.  All I find there is the Basic User Agreement, a Search window, and HELP.

The Free version installed fine and opens fine but I need to go "Pro" right away.  I'm sure I've just missed something and would really appreciate a little guidance!  Cheers!