I had an ipod Nano before I bough the Ipod classic and I want to update my nano for my mother.

My song library currently has many songs, all of which are on my ipod classic. Obviously they can't all fit on my nano and I want to put some songs on my library onto my old nano for my mother to use. I can't figure out how to do this. I plugged the old nano in and was able to delete all the content I did have on it but now I am lost. Help would be much appreciated.