Check the help in iTunes. Lots of instructions there. Note that the library is not just the songs, but also the database and album art files that iTunes uses to keep track of and display appropriate images for each song or album. That could be your problem right there-just moving the songs. Once you've got them on the Gateway, you could try using "Add to Library" to get iTunes to see them, but your play counts, ratings and so on won't be there.