Joomla! 1.5 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.

Step 1. Create a MySQL database and add a new user to it.
Step 2. Go to the Joomla download page. Download the .zip file with the latest version of Joomla! 1.5 to your computer and upload it to your host (in public_html folder as normally) by FTP software.
Step 3. Open web browser (ex: FireFox, IE,...) to access into the cpanel site (the site to manage your host) and extract .zip file.