While we don’t offer support on how to use your phone on Google Calendar, we do get many questions about how to use your WhenToWork Google Calendar on your iPhone calendar. This does require a number of steps, so we have provided some guidance here as a courtesy that we hope you find helpful.
Be sure you have exported your WhenToWork schedule to Google Calendar and confirm that you can see your shifts on it in Google Calendar.
Please see Google’s help page on this topic:
https://support.google.com/calendar/answer/151674?hl=en&ref_topic=3417927