Microsoft Outlook for Macs does not allow subscription calendars to be added. To add one, use Apple’s Calendar app.
Adding PSU events calendar(s)
Navigate to GoPSUSports.com>Schedules>Downloadable Schedules to find the events schedules (or click the link).
Pick a sport, or for all sports, use ‘All Events’.
Under ‘Sync Calendar With:’, click ‘Apple’ and allow it to use Calendar.
This will bring up the Calendar app with the Calendar URL. Click Subscribe.
You may choose whatever settings you want. The recommended settings are below: