For help with a specific page within Joomla you can click on the help toolbar icon for further information about that specific page.
The current version is Joomla! 3.3. If you are using a previous version, all help screens will still function as expected. You may encounter references to features not available in a previous version(s). You should update your Joomla! version ASAP for these new features and security updates.
If you have only recently starting working with Joomla you will probably have experienced the pain of learning a new system. New terminology, new ways of doing things, perhaps even the web itself may be new to you. Then let this guide relieve some of that pain.
Joomla! 3.3 is the current STS version of the new Joomla! 3.x series. If you need a LTS version, Joomla! 2.5 is the current LTS version and will continue to be supported until 6 months after the release of Joomla! 3.5. Here is a selection that will help you get started.
For more information see the Joomla 3.3 category page.