I know this is ridiculously late and really testing the principle of “better late than never”, but here are the slides from my November Faithful Question session titled “Why do we have the Liturgical Year?”
http://deaconken.org/presentations/Liturgical_Year.pdf
I do have video for this session and it’s currently 3rd in line to get turned into a YouTube video. Hopefully I can get it done by the end of January.