If you use iCalendar on your MacBook or have it embedded on your website, here's how you can find the link to integrate the iCal feed into your Church App:
Open the calendar on your computer:
Right-click the calendar you want to integrate:
Set the calendar to Public and select Share Calendar:
Finally, take the URL and paste it into your new calendar media source.
If the calendar is on your website, right-click the "get iCal link" under your calendar and select "copy link address", then paste that into your calendar media source.