Animate Button

I'm having trouble figuring out how to change the alpha of a button in a sequence. Here is what I'm trying to do.

I have set up a button with its alpha set to 0.5. I program the alpha to change to 1.0. The user presses the button that the alpha has changed and then the next random button's alpha changes and so on. I'm catching which buttons alpha has changed. I'm trying to get them to highlight in order there alpha changed using a "for in" with a "switch" statement. But what I'm getting is they all light up at one time instead of one at a time. I've tried using animation with delay but nothing seems to work. Any ideas?

Thanks, Bryan