[Pazvanti]

Try this:
Connect playbook to Wi-Fi. Go to Settings->About and sellect "Network" from the drop-down menu. write down the IPv4. It should be something like this: 192.168.1.100
next make sure that your PC is in the same network as the Playbook. If you use the same router to connect than it is. Open MyComputer and in the address bar type: \\IP_YOU_GOT (ex: \\192.169.1.100) and hit enter.
If done correctly you are now remotely connected to the PlayBoo FileSystem. Open the "media" folder and there you can see a folder "music" I think you know what to do from here. (HINT: Copy music from the PC to that folder)