Extend from box. Notes

I need to program a game in which you can pick-up notes. I want to make a class that extends from Cube gameobject and add a variable noteText to it. I am new to unity so I have no idea whatsoever on how to do this. Can someone give me a hint?

You won't extend from cube; you'll create a script (which extends from MonoBehaviour) and then attach it to any object (like a cube).

e.g. (C#)

public class PickupNote : MonoBehaviour
{
  public string noteText = "";

  public void OnTriggerEnter( Collider col )
  {
    // check if other object is a player
    // e.g. if( col.gameObject.tag == "Player" )

    Debug.Log("You picked up a note: " + noteText);
    Destroy(gameObject);  // kill the pickup object now that you have the note
  }
}

Yes but ehmm I want a note with variable text... I want to create like a new note ( var note :PickupNote = new PickupNote("This is a test"); ) Like that..