Quoting Incognito Ninja™:" So what are the benefits from doing it? Is there a beginners video you recommend?"
I gained strength and flexibility. I don't like a lot of traditional exercising, so yoga worked well for me. I started off going to classes, so I don't know anything about beginners videos. I'll tell you how my instructor started us off, though.
She started off by teaching us the elementary poses and some basic background. Once we had the poses down, she put them together in various combinations. After we became more comfortable with the poses, she started showing us harder variations of the poses and some more difficult poses. Then, we started incorporating those into the combinations.