Joomla is an Open Source project, which means it is developed by a community of developers. Everything from the documentation to the code itself, was created by and for the community. The Joomla community provides extensive documentation and support via their website, Joomla.org. There are also thousands of independent sites that provide information, extensions, templates, tips, tricks, hacks, you name it.
Here are some suggested resources for Joomla:
Joomla.org
The official website for the Joomla script, with comprehensive documentation and support forums to ask questions and find answers. When you are experiencing issues with Joomla, this should be your first stop for support, since common problems and their solutions are typically posted on this website. There is also a great community to whom you can pose your questions.
Extension or Template Designer's Official Website
As you work with Joomla, you may add extensions and templates to your website. When you are having an issue with a particular extension or template, it is usually best to contact the creator of that particular extension or template. You can locate this information on Joomla.org under the "Do More > Extensions" menu or by performing a search.
Try a Search Engine
Having an issue or wanting to do something in Joomla? Since Joomla powers 2.7% of the entire Web, chances are, someone else has encountered something similar, and they may have posted the solutions online. Frequently you can utilize search engines to locate whatever you may need concerning Joomla.