Connect your external calendar(s)

1) Hit the '+' button and select Google or Microsoft

2) Choose the account you'd like to connect

3) When looking to avoiding double bookings with events already scheduled within your connected calendar, hit the check box on the calendars you'd like to avoid overlapping under the Avoid column. This will ensure not time slots are shown as available when an event is already scheduled in this specific calendar 

4) Send To is where your Calendr booking will be shown in your external calendar. Be sure only to select one

5) Hit the '+' button if you'd like to connect another external calendar.