This is a common structure and it works well when each branch has its own appointment type and each dentist has an accurate working schedule.

• In Appointments, create one appointment type per branch (for example Consultation - Branch A) and set the location to that branch address.
• On each appointment type, choose Users as what is booked, add only the dentists of that branch, and allow the customer to pick the user.
• Make sure every dentist has the correct working hours, and connect their Google or Outlook calendar so other commitments block slots.
• Set the duration, minimum notice and scheduling window in the type's options, and add questions such as reason for visit.
• Publish the types on your website appointment page; patients then choose the branch type and the dentist, and only free slots appear.

If a dentist works in two branches, add them to both types and split their schedule carefully so the same hour cannot be booked twice.