Joomla is a popular content management system that can be installed onto your account through Fantastico de Luxe in your account cPanel.
From Joomla.org: Joomla is an award-winning content management system (CMS), which enables you to build Web sites and powerful online applications. Many aspects, including its ease-of-use and extensibility, have made Joomla the most popular Web site software available. Best of all, Joomla is an open source solution that is freely available to everyone.
The first step in getting started with Joomla is to install the software, which can be installed using Fantastico for free. Please see the following like for more help with Joomla installation: Installing Joomla through Fantastico
After you've installed Joomla, you can begin building your website. We recommend reading the following content on Joomla.org if it is your first time building a website with Joomla: Absolute Beginner's Guide to Joomla!
Further Joomla Documentation
Besides the Absolute Beginner's Guide to Joomla!, Joomla provides much more documentation for using the software, which you can find here: Joomla! Official Documentation