Setting the Date and Time on Your Galaxy Tab S
By default, your device receives date and time information from the wireless network. When you are outside network coverage, you may want to set date and time information manually using the date and time settings.
Date and Time Settings
From the Home screen, touch Apps > Settings.
Touch GENERAL> Date and time.
Touch the checkbox to toggle Automatic date and time ON or OFF.
Set the date, time, time zone, time format, and date format.
Set date and Set time are disabled if automatic date and time is turned on.