Complex Simon Game (HELP!)

I am currently working on my master’s degree thesis - it is a Simon-style game that adds audio notes to a dynamic timeline at the bottom of the interface. The user is then able to click and drag to re-arrange the audio notes to “remix” the sequence to their liking.

Right now, I am trying to make each button trigger one of 18 library sounds at random each time it is clicked. How do I write this into my existing code?

Here is my code so far:

import flash.geom.ColorTransform;

// Variables relating to score, pattern, etc.
var pattern = new Array();
var buttons = new Array();
buttons.push(node1, node2, node3, node4, node5, node6, node7, node8, node9, node10, node11, node12, node13, node14, node15, node16, node17, node18);
var position = 0;
var playersTurn = false;
var score = 0;

// Start generating the pattern
setTimeout(nextMove, 1000); // Call "nextMove" after 1 second
// set the text at the bottom
output.text = "Watch the sequence...";
scorebox.text = "Score: "+score;

// Tell buttons to expect clicks from mouse
node1.addEventListener(MouseEvent.CLICK, clicked);
node2.addEventListener(MouseEvent.CLICK, clicked);
node3.addEventListener(MouseEvent.CLICK, clicked);
node4.addEventListener(MouseEvent.CLICK, clicked);
node5.addEventListener(MouseEvent.CLICK, clicked);
node6.addEventListener(MouseEvent.CLICK, clicked);
node7.addEventListener(MouseEvent.CLICK, clicked);
node8.addEventListener(MouseEvent.CLICK, clicked);
node9.addEventListener(MouseEvent.CLICK, clicked);
node10.addEventListener(MouseEvent.CLICK, clicked);
node11.addEventListener(MouseEvent.CLICK, clicked);
node12.addEventListener(MouseEvent.CLICK, clicked);
node13.addEventListener(MouseEvent.CLICK, clicked);
node14.addEventListener(MouseEvent.CLICK, clicked);
node15.addEventListener(MouseEvent.CLICK, clicked);
node16.addEventListener(MouseEvent.CLICK, clicked);
node17.addEventListener(MouseEvent.CLICK, clicked);
node18.addEventListener(MouseEvent.CLICK, clicked);

// Explain to Flash what clicked means
function clicked(clickInfo:MouseEvent) {
    // Body of the function
    if (!playersTurn) return; // same as playersTurn==false;
    // Check that the clicked button was the right button
    if (clickInfo.target==pattern[position]) {
        score = score + 1; //could be written score++
        scorebox.text = "Score: "+score;
        output.text = "Yeah!";
        // Increase the position in the pattern
        position = position + 1;
        // Check to see if it's the computer's turn
        if (position==pattern.length) {
            // It's the computer's turn
            position = 0;
            playersTurn=false;
            output.text = "Watch the sequence...";
            setTimeout(nextMove, 1000);
        }
        // Play the button's animation
        clickInfo.target.gotoAndPlay(2);
    } else {
        // Game Over stuff
        output.text = "Game Over";
        playersTurn = false;
        //Play the button they should have clicked
        pattern[position].gotoAndPlay(2);
        // gray out the button they did click
        clickInfo.target.transform.colorTransform = new ColorTransform(0.5, 0.5, 0.5);
        // reset the game after a few seconds
        setTimeout(restartGame, 3000);
    } 
}

function nextMove() {
    // If there are buttons left to play through, play them first
    if (position<pattern.length) {
        pattern[position].play();
        position++; //position=position + 1;
        setTimeout(nextMove, 1000/(1+pattern.length/10));
    } else {
      // Generate a random number between 0 and 17
      var randomNumber = Math.floor(Math.random()*18);
      pattern.push(buttons[randomNumber]);
      buttons[randomNumber].gotoAndPlay(2);
      playersTurn = true;
      output.text = "Repeat the sequence...";
      position = 0;
    }
}

function restartGame() {
    // reset everything and start again
    pattern = new Array();
    position = 0;
    playersTurn = false;
    score = 0;
    // loop through the buttons to reset their color transforms
    for (var i=0; i<buttons.length; i++) {
        buttons*.transform.colorTransform = new ColorTransform();
    }
    // Start generating the pattern
    setTimeout(nextMove, 1000); // Call "nextMove" after 1 second
    // set the text at the bottom
    output.text = "Watch the sequence...";
    scorebox.text = "Score: "+score;
}