This video will take you through the correct way to use composer dependencies in Drupal 7 and Drupal 8 using the Composer Manager module. This video part 2 to the PSR video we did last month, that shows how to write a views handler using PSR-4 class autoloading (http://activelamp.com/videos/psr-4-class-autoloading-with-drupal-7). At the end of the PSR-4 video, I pulled in a composer dependency not using Composer Manager. This video will show you the correct way to use Composer with Drupal.