Help with Gravity Tutorial

It is exactly what I need but I need some preliminary information.

http://www.kirupa.com/developer/actionscript/gravity.htm

I just need the ball to drop straight down. No bouncing.

When I create the movieclip is it one keyframe or do I add 2 keyframes with a motion tween between them. If so where do I add the actionscript? On the 1st keyframe?

Thanks