Could some one elaborate on this tutorial for me

http://www.kirupa.com/developer/mx2004/ani_smartclipnav2.htm
OK, at the end of this tutorial it talks about adding links to the buttons created. I did what it said to do but the two buttons keep canceling themselves out if I place them on top of eachother. Could some one please shed some light on how to place them.
thanks
CLoak