Singletons in music script?

Ok, I’ve been searching around for awhile for a music playing script that continues across scenes but destroys when it returns to the first scene, I finally found one. But this script calls for MyUnitySingleton, which first of all I have no idea how to declare or make a singleton for it to reference to. Here is the link to the code.

http://answers.unity3d.com/questions/11314/audio-or-music-to-continue-playing-between-scene-c.html

I don’t know what the MyUnitySingleton is that they are referring to. I’m trying to use the second commented code:

The first function:

private static var instance:MyUnitySingleton;
public static function GetInstance() : MyUnitySingleton {
return instance;
}

function Awake() {
    if (instance != null && instance != this) {
        Destroy(this.gameObject);
        return;
    } else {
        instance = this;
    }
    DontDestroyOnLoad(this.gameObject);
}

And the second:

var NewMusic: AudioClip; //Pick an audio track to play.

function Awake ()
     {
          var go = GameObject.Find("Game Music"); //Finds the game object called Game Music, if it goes by a different name, change this.
          go.audio.clip = NewMusic; //Replaces the old audio with the new one set in the inspector.
          go.audio.Play(); //Plays the audio.
     }

Help on what a singleton is, how to make one/declare one, and how to get this script to work would be great.

MyUnitySingleton is just the name of the script where you are using that pattern. Change it to whatever your script is (eg. MusicScript).