What is availability?

From TherapyCharts

Adding availability to your schedule allows support staff to see when a clinician is willing to accept appointments. For some clinicians, it is also a way to earmark time spent in the office for patients, paperwork, or other business related tasks.

To add availability Configuration Tab -> Application Preferences: Calendaring and Scheduling, then use the grid to add or remove daily availability for the various clinical staff in your office.