I got a new laptop but my iPhone won't download the new music?

So I have an old laptop that has over 1000 songs but it is so painfully slow when downloading new music. I finally got a new laptop that has no music on the iTunes library so I downloaded about 10 songs to my new MacBook. However, when I connected my iPhone to the new MacBook, I could not add these new songs to my phone. The old laptop is almost completely busted and I really don't want to have to bring the old laptop to college next week, but I really want to download new music help.

You probably have to click authorize device to your itunes account.