Overview
Install additional functionality and styles with addon modules and themes, contributed by members like you, and free here at drupal.org
Installing modules
Various information about how to install Drupal 7 modules
Installing themes
Instructions for installing a contrib theme on Drupal 7
Moving modules and themes
How to move modules/themes and fix potential problems.
Uninstalling modules
How to properly uninstall a module.
Directory precedence and multi-site considerations
Directory Precedence