The website we will be using is : http://www.youtube-mp3.org
1 step : find a video you would like the mp3 file of.
2 step : Copy the link bar of this video
3 : after you have copied that go to http://www.youtube-mp3.org/
4 : when your on the site, put the copied youtube link in the bar.
5 : click convert.
6 : after you have clicked convert you should be getting page like this.
7 : at that page hit download, and then a save dialog should pop up.
save the mp3 file at a place, and your done!
That was it 🙂