Joomla Template Overrides are used to allow the developers to make changes to the layout of a module or component without having to hack into the Joomla core of the module code.
The folllowing tutorial will give you a step by step process to follow for creating Joomla article in Joomla administrator.
In this tutorial let see how to create new menu and add add article content to created menu in Joomla2.5 in details.