In Teams/Group calendars (Round Robin, Service, Class, and Collective Calendars), appointments assigned to a particular user can be synced to Third Party Calendars (Google / Outlook / iCloud) and the events from Third Party Calendars can be read and synced to the CRM.
You can configure your calendar under Settings > My Profile. There are primarily two settings, Primary Calendar and Check for Conflicts. All the third party calendar integrations added by the User are shown here.
Primary Calendar
The Primary Calendar is the main calendar responsible for writing events to Google, Outlook or iCloud. It also reads events from Third Party Calendars, but its primary responsibility is to push new appointments to these calendars.
If Contact creation is enabled, it functions like an Event (Unassigned) Calendar's two-way sync. To summarize, events with attendees in Google / Outlook will be converted to appointments, except for recurring events.
Primary Calendar Dropdown:
Here, all the calendars integrated by the particular profile will be displayed. Disabled calendars may either be included in 'Check for conflicts' or may lack write access to Google.
Allow Contact Creation:
If you wish to create appointments from Google/Outlook Calendar, select this option; otherwise, leave it as None.
If you want events from Google/Outlook with attendees to be created as appointments/contacts, select one of the calendars from the dropdown. This ensures appointments are created in that specific Calendar. All group calendars that the user is part of are listed in this dropdown.
Allow Trigger:
This dropdown only appears if a calendar is selected from Contact creation. It applies only to appointments created from Google/Outlook. If selected, the trigger will fire for appointments created due to synchronization; otherwise, it will skip the trigger.