Locale: Set up your Local and Internationalization Settings on this page.
Default Site Language: Set default language for your front end site (Customers and Visitors)
Select your Time Zone: Default Time zone will be set as per your selection.
Date Format: You can select Date format from the given options or you can give your own custom rule.
Time Format: You can select Time format from the given options or you can give your own custom rule.
Learn more about PHP dates and time at http://php.net/manual/en/function.date.php