Convert music to computer then iphone?

Ok so i converted some youtube song links on the computer to mp3 and saved them in my music documents and i don't know how to get them to my iphone now?

Download itools its Japanese made but has English version. You can drag n drop any file movies, music, pics, even apps. Its good for non jailbroken iPhones cause you can get free apps off torrents n just use itools to put it on your idevice.

Drag the files from your music document into iTunes.