Overview
A prebooked appointment is defined as a future appointment that is scheduled during the same calendar day of a client's service. Boulevard updates the prebook % stat in 15 minute increments or less. Please note that if a client prebooks an appointment and then cancels it the appointment will still count towards the prebook % stat.
Prebooking a Future Appointment
Go to the Checkout screen
On the left, click Prebook to choose a date in the current calendar view or 4w, 6w, or 8w for convenient jumping ahead that amount of weeks

Now in the New Appointment window, add the service(s) and click Select Time
Click on the new desired date and time on the calendar and then Done

Select if you want the client to receive an emailed confirmation, and then Complete Booking

With the prebooked appointment complete, now expand the Checkout window on the bottom right and fully check out the current appointment