How do you.....?

programming flash
1

I have a movie clip that I want to have fade in on the stage, stay for a while and then fade out. Here is the code that I have so far:

import mx.transitions.Tween;
import mx.transitions.easing.*;
var logoTween:Tween = new Tween(myLogo_mc, “_alpha”, Regular.easeIn, 0, 100, 36, false);
logoTween.onMotionFinished = function() {
if (!this.runOnce) {
this.runOnce = true;
this.yoyo();
} else {
delete this.onMotionFinished;
}
};

How can I achieve this?