The instructions are very clear and the steps are easy, thus you won’t have any problem following them regardless of your experience level.
This app allows you to upload and download music to and from your Google Music account.
So you need to download, install and open it (it’s free by the way).
That's especially important if you let the app cache music as it plays. The APK is signed by Google and upgrades your existing app.
Public playlists were added to Play Music a while back, but now the app can find them in search results. The cryptographic signature guarantees that the file is safe to install and was not tampered with in any way.
Also, this process requires you to have plenty of free space in your hard drive and some good bandwidth, as you’re going to download your entire Google Music Library to your computer.