Automatic Appointment Confirmations for Online Bookings are set per appointment type and, unlike Reminders, they don't use the existing confirmation settings found on the Settings > Appointment Book > Confirmations page.

Go to the Settings > Online Booking > Services page.

Select the Service that you want to edit by clicking on it's name.

Click on an Appointment Type.
​

Click Edit at the top of the page.

Enable or Disable Confirmations for Email and/or SMS confirmations using the toggles.

Select the Template that you would like to use.

Click Save.

Repeat this process for each Appointment Type.