I am sure you all have at least one calendar on your Mac. Many of you probably more than one calendar. In the last few iterations of the macOS you have the capability of “Sharing” a calendar with other people. You can also “Subscribe” to calendars as long as you have the correct address from the Internet or perhaps in a Email. This article explains how to Share, Subscribe and Unsubscribe from calendars. It is not difficult to do. You might find it helpful.