How to use SSL on Mac running Server

I have a Mac mini running Server on which I want to run the calibre Content Server. For added security I want to access calibre using SSL, but I’ve been unsuccessful.

I can access my website on the Mac mini (using https), but I can’t access calibre (when I append the 8080 port number to the URL).

I suspect that I need to fill in two fields in the “Sharing over the net” Preferences panel: (1) Path to the SSL certificate file and (2) Path to the SSL private key file.

Can anyone confirm that I am on the right path? (No pun intended)

And if so, where can I find these two files on a Mac system?