GUISkin Problem

i write menu script easily, but i cant to put any GUISkin, there is my code.

/* GUI.Button example */

var GUISkin:GUISkin;
// JavaScript
function OnGUI () {
GUI.Box (Rect (140,90,180,230), "MENU");
	if (GUI.Button (Rect (170, 120, 120, 30), "Play Alone")) {
		// chatvirtviskodi
	}
		if (GUI.Button (Rect (170, 160, 120, 30), "1 VS Computer")) {
		// chatvirtviskodi
	}
			if (GUI.Button (Rect (170, 200, 120, 30), "1 VS 1")) {
		// chatvirtviskodi
	}
				if (GUI.Button (Rect (170, 240, 120, 30), "Multyplayer")) {
		// chatvirtviskodi
	}
					if (GUI.Button (Rect (170, 280, 120, 30), "Exit")) {
		// chatvirtviskodi
	}
	
}

You’re not doing anything with the skin. See the docs for GUI.skin.