The easiest way is probably to create a calendar and contacts list with a network provider such as gmail or outlook.com or yahoo and sync with TB, using the TbSync and related add-ons. Calendars and contacts can also be added directly with CalDAV and CardDAV.

https://addons.thunderbird.net/en-us/thunderbird/addon/tbsync/

https://support.mozilla.org/en-US/questions/1304356#answer-1368791

https://addons.thunderbird.net/en-US/thunderbird/addon/addressbooks-synchronizer/

This is a work around that I had already thought of. I really hate to share my any information with gmail, outlook.com, yahoo, etc. then I have to. I was hoping that someone had an add-on or that Mozilla would have something that is similar to the sync in Firefox. I really like the sync in Firefox because it keeps all the bookmarks, etc. current across all the different systems and computers I use. Thanks for your answer. I will leave this out here for a bit to see if anyone else has an idea that is not such a work around.

the TB sync addon you were linked to will sync any card dav provider, you are more than welcome to run your own card dav instance on your local network so you share nothing with anyone but yourself. https://en.wikipedia.org/wiki/Comparison_of_CalDAV_and_CardDAV_implementations Or https://devguide.calconnect.org/CardDAV/Server-Implementations/

Offer some links to server implementations you could perhaps use.