Calendar – Outlook Mac/Office 365
Navigate to the calendar on Office 365 online:
https://outlook.office365.com/owa/?path=/calendar/view/Week
Click on Add Calendar on the top
Then select From Internet

In the box, paste this address:

Click save.
iPhone
If this calendar account is already on your phone, the nursery calendar should now appear on it it after a short delay. If not, click on iPhone instructions
Android – you will need to add this calendar to a Gmail account on a computer first, before it will appear on an Android phone.