What is Drupal?
Drupal is a free, open-source web development platform for online content and user communities. Drupal powers some of the busiest sites on the web, and can be adapted to virtually any visual design. Drupal runs over a million sites, including WhiteHouse.gov, World Economic Forum, Stanford University, and Examiner.com.. Source
Using Softaculous (from your cPanel) to install Drupal is a simple one click, it will even keep itself up to date for you