I bought an ipod shuffle about a dozen years ago and put some iTunes on it. Fast forward a couple of years and I bought a nano and put iTunes on it from a different computer. I am trying to move the shuffle songs to the nano, but cant seem to do it. No matter if I plug the shuffle or nano in, I get the current library. when I plug in the shuffle, it appears momentarily 'on top of' the current iTunes library and then disappears, never to find it. Help please.