Another button question

I have a question regarding buttons. I am a noob and this question has most likley been answered before, yet I cannot find the answer. I want to create pop-up windows in my flash document. On the timeline I have buttons that I want to use to play the pop-ups when you click on them. The pop ups are self contained movie clips that have a bit of animation and pics on them. I dragged each mc onto the stage. The problem I am having is the movies start to play when the flash document is loaded. I want my main graphic (artwork) to stay in place on the stage and when you click a button the approate pop-up(movie-clip) will play, It’s seems when I do it they play regardless. How can I activate movie clips from buttons on the stage.

I have been using the action:

on(rollOver) {
_root.popup_1.play();
}
With this method do I still have to drag the MC onto the stage, if I do how do I stop it from auto playing and only play when the button is rolled-over. Thanks in advance.