From your Google calendar page on the web, you should see a section on the left titled ‘Other Calenders’. There’s a wee menu button there tagged ‘Add’, left click on that and select ‘Add by URL’. Put the following URL into the box:
and click ‘Add Calendar’.
That should be it, the calendar should appear in the other ‘Other Calendars’ section.
Once the calendar is added to your Google calendar account, as above, it should just appear, as if by magic, on your Android phones.