Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 765)

Turn the < > dial to select the time zone, then press < >.
If your time zone is not listed, press the < > button, then set the
difference from UTC in [ Time difference ].
Turn the < > dial to select a [ Time difference ] item (+/–/hour/
minute), then press < >.
Turn the < > dial, then press < >.
After entering the time zone or time difference, turn the < > dial to
select [ OK ], then press < >.
3.
Set the date and time.
Turn the < > dial to select an item, then press < >.
Turn the < > dial, then press < >.
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