From Admin tab (bottom of screen) -> Lists -> List item entry -> Appointment task type…

You can create many appointment task types that have the behavior of "Non Patient Care" These are the types of "Appointments" that are not for any particular patient but rather allow you to block off staff time. For example: Holiday, Out of Office, Conference, etc. 

You can add additional task types by directly typing in the bottom, blank row (below “out of office” in the example below)

Select the date on calendar you wish to block -> right click to create new appointment.

Enter new appt type on calendar and add as all day appt or specific time (eg. 8am -5pm). Appointment can be made with recurrence as well. Select Save to save and refresh the Scheduler screen.