To download video from YouTube very easy:
1)First of all you need find interesting video on YouTube.
2)After that put your video link into the input.
3)Push big button GO on the right of the screen.
4)After that you will see list of available videos with different resolution, file extensions and buttons for downloading:
5)Choose the best video in list for you and click link download:
6)If its Google Chrome, you will see player with video and little icon download video on screen. Click it for saving on disk. Also you can share link with your friends. For that you should click button *Copy* and give link to another people.