When viewing the booking click on the [Services] link in the left hand menu while on the booking screen.

On the next page you will see the services currently added to the booking. You can schedule the service for a particular date and time by entering the required date/time into the input fields, you can also set a duration and assign the service to a staff member, and add notes.

If you need to delete the service you can do so by clicking on the red [X] button next to the service.