To specify startup and shutdown times for a group of workstations, open the Computer panel, and click the Control tab. Select the appropriate check boxes for scheduled shut down and startup times, and specify the time for each.
Workstations may not shut down on schedule if they are connected to the server at the login screen. To avoid this, select "Disconnect from the server if no user logs in within <> minutes," and specify a suitable amount of time. This ensures that idle clients are ready to be shut down when scheduled.