A coordinated appointment consists of time with both dentist and hygienist.
This feature can be enabled from Configure > Appointment Book.

Coordinated Duties Appointments - Benefits and Restrictions

Once Co-Duties is enabled appointments will then ask for the Dentist and/or Hygienist instead of one field for Provider.
The Coduty Grid is a timeline of the patient appointment, allowing you to define which type of provider is required for each part of the appointment.

To make appointment booking as automated as possible this information is usually pre-defined for each appropriate service such as EXH (exam followed by hygienist) or HEX (hygienist followed by exam). However, you can manually override this automation to accommodate individual patient requirements. EXACT restricts charting time on the grid to a maximum of 4-6 hours, depending on the appointment book's time interval setting:

You can stagger appointments (they don't have to be continuous) and even leaves gaps in between if required.

You can add/edit service so that the grid time is fixed so it won’t require any manual editing before booking a Co-duty appointment. Also tick the box for “list in quick book services” so it’s available from the edit appointment window for quick selection.