Auto-date & time: Checkmark to use the network-provided date and time.
Set date: Tap to manually set the date to use for your phone. This setting is grayed-out when the Auto-date & time setting is checkmarked.
Set time: Tap to manually set the time to use for your phone. This setting is grayed-out when the Auto-date & time setting is checkmarked.
Auto-time zone: Checkmark to use the network-provided time zone.
Select time zone: Tap to select a time zone other than the one provided by the network. This setting is grayed-out when the Auto-time zone setting is checkmarked.
Use 24-hour format: Checkmark to display the time using the 24-hour time format (for example, 13:00 instead of 1:00 pm).