Microsoft 365 (Apple Calendar 10.9) - Subscribing to an Internet calendar
This document explains how to subscribe to an Internet calendar in Apple Calendar for OS X 10.9.
Subscribing to an Internet calendar
Open Apple Calendar, and from the Calendar menu at the top of the screen, select File and then click New Calendar Subscription. A dialogue box will appear.
Enter the URL of the Internet calendar to which you would like to subscribe. URLs will take the format https://example.com/calendar.ics. Once the URL is entered, click Subscribe.
An "Info" form will appear containing the settings for your newly-subscribed-to calendar. Here you may change the name and color of the calendar, change the subscription address, remove any alerts and attachments from the calendar, adjust the frequency with which the calendar refreshes its information, or you can choose to ignore alerts from the calendar. Adjust these settings if needed/desired, and click OK.
Your new calendar will appear under "Other" in the left-had column of calendars.