This page explains various types of authentication / authorization scenarios.

Here is the video tutorial for the same:

<iframe width="560" height="315" src="https://www.youtube.com/embed/AGyyYEd4Akw?list=PLmua155_WrDyoe7dYDB3lCfh-UK4XicT6?ecver=1" frameborder="0" allowfullscreen></iframe>