all my music is in the "cloud" and now i can't add it to my ipod

I bought a new computer and installed itunes on it. all my music was saved on an external hard drive, so i connected it to the new computer, opened itunes and there was all my music. BUT each album has a little cloud in the corner of the album art. when i synced my ipod to the computer today to add new music it says i have to download from the cloud to add. ***?