How do I make one function trigger another one.

Question

     The best way I can describe what I am looking for is to say that I am working on a project that once you click the button at the begining it plays a movieclip and has a few different scenes throughout the project. So what I need is when you click the button the first mc plays and when the first mc is done it triggers a second one to play without needing to hit a button. I hope this is just something simple I am missing.
Thanks!
--Logan
F-CS6

Answer 1

Putting all together I now came up with two issues. The original one with the trigger and now the button decided to stop working after it worked fine. 
   public class maythe4thfinal extends MovieClip
        public function maythe4thfinal()
            opening.buttonMode = true;
            opening.addEventListener(MouseEvent.CLICK, moveIt);
        private function moveIt(evt:MouseEvent):void
            opening.visible = false;
            this.swbg.gotoAndPlay(2);
            this.farfar.gotoAndPlay(2);
            this.swbg.addEventListener(Event.ENTER_FRAME, scroller2);
        private function scroller2(evt:Event):void
            if (this.farfar.currentFrame == 55)
                this.scroller2.gotoAndPlay(2);