Perhaps silly queston about registering new product

I have a License code that I would like to enter using the Help menu link.

However, how do we access the application to begin with so that we can open it and complete this function? For some reason, I’m stumped. Thank you

The applications are available for download at

Note that the current versions require the Tiger or Leopard operating system. There’s a link on the download page to legacy versions that run on OS X 10.3.9 or earlier.