Instructions
Power on the PlayStation. Select "Settings," then "System Update," then "Update via Internet." The PlayStation will check for any available updates. If any are detected, follow the onscreen instructions to download them and begin the installation.
Connect a USB drive containing your own music to the PlayStation 3's USB port.
Insert the Metal Gear Sold 4 game and load it.
Press the "PS" button in the center of the controller to load the in-game XMB (menu system). Select the "Music" tab, select the USB drive and select the desired music to begin playback.