If your calendar app isn't listed by name, use the Other calendar option. It works with any calendar that supports subscribing to an internet (iCal) feed.
Steps to sync:
From the URUNN Settings screen, tap on Apps & devices.
Tap on Calendar Sync, then select Other calendar.
Copy the displayed URL by tapping the copy icon to the right of the link (a green checkmark confirms it's copied).
In your calendar app, choose the option to add a calendar from a URL or by subscription, and paste the URL you copied.
Save to finish. Your URUNN plan will appear in that calendar.
What to expect: your training plan is added as a read-only, auto-updating calendar subscription. It refreshes when your plan changes and can't be edited from your calendar app.