Simply connect your iPod to your Mac/PC with your connector. Make sure 你 have iTunes already installed. After 你 connect the iPod, it should automatically sync your music, videos, movies, etc. To iTunes. If 你 need additional help, go to Apple's website at apple.com
if your asking TO itunes FROM an iPod, it'll only transfer songs that 你 bought from itunes, not CD ripped songs 或者 songs downloaded from anywhere else. (I found out the hard way :()