After visiting music.google.com and agreeing to Google's terms of service, you'll be shown an options page for receiving promotional music from Google. If you opt in, you can select what specific genres of music you're interested in receiving.
Next, you'll need to tell the Music Manager application where you store our music on your computer. iTunes is selected by default, but you can also configure Windows Media Player or a specific media folder.
Beyond the ability to stream songs online using the Music Beta site, Android users are encouraged to download the free app. Using the app, you can download any song in your collection and cache your recently played songs for offline listening.