You can add more Appointment statuses and change the colors of them by clicking on the Lists tab (note that only the Headquarters Administrator has access to this button).

From this section of the application, click on the Appointment Status Types link, which will list the current statuses set for your account.

By default, the system offers

Scheduled

Confirmed

Complete

and No Show

Click any of the default status names, if you wish to change the associated color.

To add a new status, click Add New Appointment Status Type. Enter a description for the status, select a color and click Save.

Once you add a new status, you can then place Appointments into that status when updating them in the Appointments section of Site Administration.

See article How Can I add more Appointment Status Types/Colors for more information.