How do you know if a song is creative commons? I need to add music to a video, but I don't know what sites have music you can add to videos without violating copyright?

You can try googling "royalty-free music". I used the website below throughout high school, it has a large variety of catchy instrumentals

http://incompetech.com/music/royalty-free/

You can use http://search.creativecommon s.org