Calendar Setup Help
To subscribe to calenars in iOS, you need to go to your Settings and add an "account". Screenshots below are from iOS 11.1.1 and are subject to change at the whim of the Geniuses at Apple.
Go to Settings, then "Accounts & Passwords"
Choose "Add Account"
Choose "Add Subscribed Calendar"
Paste in the .ics link to your subscribed calendar.
Change the name of the calendar to suit your needs.