If you are interested to contribute to drupal then first register to drupal.org site first. Then register to IRC freenode.net chat system.
Second step: go to http://drupalmentoring.org/ site and register there with same username, which you took in drupal and IRC. Good practice would be you need to take same username in all the site.
Join us for Drupal core contribution mentoring, Tuesdays 02:00 – 04:00 UTC and Wednesdays 16:00 – 18:00 UTC in #drupal IRC . (Can’t wait for core mentoring? You can find tasks on your own, too!)
Go to this chat session and work on task. Select someone as your mentor and start working on drupal.
check following URL: