You need to create a user profile or SSID to which you apply a schedule. For User Profiles, you must first turn Availability Schedule On.
You can create an availability schedule for network SSIDs to determine when they are available for access and for User Profiles to make the user profile available for specific dates, days, and times.
Note
To apply your SSID availability schedule to a wireless network, you must activate it in the Additional Settings section of the Standard Wireless Networks configuration page. See Configure Enterprise SSID Authentication.