To download the calendar to your computer, use the icon that looks like a downward pointing arrow. 

🙁 Safari Users

Safari users may be unable to access this resource because of an issue with one or more Safari extensions (see https://discussions.apple.com/thread/255206799). You can try fiddling with your extensions, or you could try using Firefox or Chrome. When something doesn't work on the Internet, trying a different web browser can alleviate some issues.