The easiest way to wrap your head around how modules work is to try installing and configuring a couple of them. This section will cover how to install, enable, and configure a contributed module called Module Filter, which can be downloaded from Drupal.org.
Check your version
This video covers a topic in Drupal 7 which may or may not be the version you're using. We're keeping this tutorial online as a courtesy to users of Drupal 7, but we consider it archived.