The Calendar Overlays feature lets you create a combined view of your calendars by layering more calendars on top of the master calendar. This means that you can have separate Calendars with different Events, but you can combine your Calendars as Calendar Overlays and see all of your Events at once. By default, all events from the calendar overlay show up when you add that overlay to another calendar.
If you use Event Tags, you have the option of filtering what events are shown from your calendar overlays. “Event Tags” are tags that you can use to label and color-code your Calendar Events. This means that if you only want to see events marked with the tag "Meeting" then only those events from that calendar will show up when you add that calendar as an overlay.
First, you'll need to add an Overlay to your calendar. Then you can learn how to filter your Overlay events using Event Tags by following these steps:
Any events that are marked with the Event Tags that you've clicked on the checkbox for will now show up in your calendar overlay. Any events not marked with those tags will not show up. You can choose as few or as many tags as you'd like.