The Appointment Scheduling feature will be available from release 0.90.
The appointment scheduling module is for enabling the users to primarily Create and Manage Appointments across services and providers. The links below will provide the steps to configure and set up the appointment scheduling module for an implementation. You will find the steps to use the module in the user guide here.
Also, please note that you may have to specify your user's permissions to allow appointment scheduling. To grant the user permission, please head over to your OpenMRS settings, then in manage users, type in your user, and grant it the permissions "appointmentmanage" and "appointments:fullaccess."