This page is primarily about removing unwanted calendars, particularly if a teacher has archived a google classroom or taken no steps to shut a google classroom down. To learn more about actually using google classroom, visit this page.
Each google classroom has a calendar.
If you unenroll from a class, the calendar is automatically removed.
If, however, the class remains active or is archived - the calendar remains.
If you have never used your google calendar, then when first visiting is that every calendar shared with you is turned "on". In the summer that may not be overwhleming, but if it is in the middle of the year it may be. So, feel free to uncheck some while while you are here. (You can get to your calendar via the App Launcher or by going to calendar.google.com). The one with your name is the calendar that you fully control and will show anything you've been specifically invited to or scheduled yourself.
To remove a calendar from the list, you need to unsubscribe from the calendar. To do this, hover over the calendar name in the sidebar and an "X" will appear. Clicking X will permanently remove the calendar from your list. (See image below)
To temporarily remove a calendar from your list: To do this, hover over the calendar name in the sidebar and click the three dots. A menu will appear. "Display this only" will check that calendar and uncheck all others (make it display only that one). "Hide from list" is a way of temporarily making a calendar go away. "Settings" is only useful for calendars you are keeping.
NOTE: If you navigate to settings and choose "Remove" it then brings you to an "Unsubscribe Button" - so it is basically the same thing as unsubscribing only with more steps (when you are not the calendar owner).
Hovering makes an "X" and the three dot menu appear.
The top two choices when you click the three dot menu after hovering over a calendar name.