What is a one-sentence summary of the following article?
When you first sign in to Google Play Music, there will be a link in the top-right corner that says "Upload Music." Click this link and you will be taken to the download page for Music Manager. Download and install the program. You will be prompted to enter your Google login information. After you sign in, you will be asked if you wish to upload songs, or download them. Select Upload and click next. Music Manager will ask where it should scan for music files. If you use iTunes, select the first option and Music Manager will convert your iTunes files so that they can be added to your library. If you have a library built in Windows Media Player, choose the second option to import the files. You can also tell Music Manager where to look specifically on your computer, including My Music folder or any other folder you specify. Music Manager will automatically begin uploading your songs to your Google Play Music account. This could take quite a while depending on your connection. Any new songs that are added to the folders that you specify are automatically added to your Google Play Music library when the Music Manager is running. You can upload up to 20,000 of your own songs for free. Any song you purchase from the Google Play Store is added to your library. These songs do not count towards your 20,000 song limit. They can be downloaded to your computer through the Music Manager.
Download the Music Manager. Sign in to Music Manager. Add your library. Wait for songs to upload. Add more music.