Send to back and add timings

1

hi below is my code
it crossfades coloured squares, but they appear on the top layer when i need them to be the back layer, could someone show me what code would send it backwards?
also instead of the on click event id just like them to play automatically
thanks

import fl.transitions.Tween;
import fl.transitions.easing.*;
import fl.transitions.TweenEvent;
var shp1:Shape = new Shape();
var shp2:Shape = new Shape();
var shp3:Shape = new Shape();
shp1.graphics.beginFill(0x0099FF);
shp1.graphics.drawRect(400,0,400,400);
shp1.graphics.endFill();
shp2.graphics.beginFill(0x00FF00);
shp2.graphics.drawRect(400,0,400,400);
shp2.graphics.endFill();
shp3.graphics.beginFill(0xCC0000);
shp3.graphics.drawRect(400,0,400,400);
shp3.graphics.endFill();
shp1.alpha = 0;
addChild(shp1);
addChild(shp2);
addChild(shp3);
stage.addEventListener(MouseEvent.CLICK, clicked);
function crossfade(e:Event):void
{
    var start:int = int(shp1.alpha > 0.5);
    var fin:int = int(!start);
    
    var tween1:Tween = new Tween(shp1, "alpha", None.easeNone, start, fin, 1, true);
    var tween2:Tween = new Tween(shp2, "alpha", None.easeNone, fin, start, 1, true);
    var tween3:Tween = new Tween(shp3, "alpha", None.easeNone, start, fin, 1, true);
}