How to rename my music in my iTunes library on my computer?

I recently got my new iPhone 5 and I want to sync all my music on my laptop onto my iPhone. I downloaded all my songs from YouTube through mp3 rocket then I downloaded iTunes on my hp laptop. When I was ready to play a few songs I saw that almost all my songs were found with the name "unknown" Can someone please tell me how I can rename my music or at least fix this problem?

Look I can't answer you directly but I can tell you how I do things, I download my songs from youtube and the info is messed up, so I put it to my iTunes library pressing the edit info option and adding the album the artist and the cover photo, I own an iPod Classic and have all my music there and it is fine.