Where would I put the onEnterFrame function?

Hey all,

I am controlling a movieclips’ properties with some buttons. I’d like to just keep a button pressed down and it continuously change, but at current time…I have to keep pressing the button.

I know it needs the onEnterFrame function, but anytime I put it anywhere…it does not work.

Here is the file:
http://ata.saic.com/media/aj/buttons%20navigation.fla

Any help would be appreciated.
Thanks in advance!