Adding New Drupal Themes and Modules
One of the best things about Drupal is that developers are constantly contributing new themes and new modules. You can extend Drupal's functionality in incredible ways by adding new modules. You can create an extremely professional-looking site in minutes by finding the right theme.
With Drupal 7, there are now two ways to add modules and themes to your site. You may either download the file and install it manually, or tell Drupal where the file is on the web and make Drupal do most of the work.
Here are the major steps you take to download and add new contributed modules and themes to your site automatically:
Locate a new module or theme you want to use on your site and copy the URL.
Give Drupal the URL for the file.
Enable the new module or theme on your Drupal site.
Customize your new module or theme as desired.
The first step for both techniques is to find new modules and themes. For new modules and themes, head over to Drupal.org and click the Download & Extend link on the top right corner of the page to browse around.
Click the Modules or Themes tab to use a form to browse or search through the available files.
For both Modules and Themes, select 7.x from the Filter by Compatibility drop-down list to make sure you see only modules or themes that are compatible with your Drupal 7 installation.
You can find especially popular modules and themes on drupal.org by selecting Most Installed from the Sort By drop-down list when using the search form on the Modules and Themes pages. This lists the modules or themes in order of the most frequently downloaded to the least.