setting the text of an instantiated prefab's child's guitext object

Hi - i’m instantiating a prefab at runtime, and trying to set the gui text of a nested gameobject, but my syntax isn’t working. This is my code:

var scoreBoard = Instantiate(scoreBoard, Vector3 (0, 0, 0), Quaternion.identity);
var yourScore = transform.Find("YourScore"); //YourScore is a child of scoreBoard.
yourScore.GetComponent(GUIText).text = userScore; //yourScore has a GUIText attached to it, and userScore is a stored String.

how do I do this properly?

Seems you mean:

var yourScore = scoreBoard.transform.Find("YourScore"); //YourScore is a child of scoreBoard