If you are logged into your Google account(if not it will ask you to log in), you can add this calendar by clicking the + plus symbol in the lower right hand corner of the calendar above. 

It looks like this:

This will add the calendar to your calendars list, on your Android phone, make sure that synchronization is checked in the calendar app settings on your phone.

Otherwise you can use the links below to the calendar:

pub link: https://calendar.google.com/calendar/embed?src=trppb0ks5hj6ths5138un95320%40group.calendar.google.com&ctz=America%2FDenver

ical link: https://calendar.google.com/calendar/ical/trppb0ks5hj6ths5138un95320%40group.calendar.google.com/public/basic.ics

To subscibe to the calendar on your ios device, see: Add Google Calendar to iOS