Importing Music Library from iTunes to a New iMac

I just purchased a new iMac, and I'm trying to import the iTunes music library from my old one to my new one through home sharing. (The music I purchased directly from iTunes automatically showed up on the new computer once I logged in, but I'm trying to get the rest of my library onto the new iMac.)

I opened up home sharing on both computers, and I was able to see my complete library on the new one. But I can't figure out how to list ONLY the music that's not currently on the new computer and also how to import that music. I recall in the past being able to easily move the music not currently in my library onto the new computer, but I don't see a way to select that music and then import it. Can anyone tell me step by step what to do?

Thanks!