Actionscript to playback to a certain frame

you need to make sure that your button is a button not a movie clip.
then enter the following:
on (release) {
//Movieclip GotoAndStop Behavior
_root.gotoAndStop("5");
//End Behavior

}

were it says 5 change to another frame number also change stop to play if you want it to auto play.

Try action script 2.0 it is easier to use:

First click on your symbol and got the behaviors menu
Then click the + symbol movie clip goto and stop or play
then click absolute and type in the frame you want