creating shapes with blend modes in actionscript 3

Ok I'm having a lot of trouble with ActionScript 3. I'm supposed to make five buttons that when clicked show a different blend mode using 2 or more shapes. Each of these blend modes also has to have a text box explaining what the blend mode does.  The assignment requires only one layer which is the actions layer. Everything has to be made using script only, which is why I'm having so many problems.
Can someone please help me with this and simplify it has much as possible. I need to have some sort of answer sometime tomorrow. I thank anyone who helps.

I have this code so far.

import flash.text.TextField;

import flash.text.TextFormat;

import flash.net.URLLoader;

import flash.net.URLRequest;

import flash.events.MouseEvent;

import flash.display.Shape;

//create button instances

var btn:darkBtn = new darkBtn;

var btn2:invertBtn = new invertBtn;

var btn3:overBtn = new overBtn;

var btn4:screenBtn = new screenBtn;

var btn5:subBtn = new subBtn;

//add our interface objects to the main display list

addChild(btn);

addChild(btn2);

addChild(btn3);

addChild(btn4);

addChild(btn5);

//button positions

btn.x = 12;

btn.y = 395;

btn2.x = 131;

btn2.y = 395;

btn3.x = 250;

btn3.y = 395;

btn4.x = 367;

btn4.y = 395;

btn5.x = 485;

btn5.y = 395;

//create a new font

var mainFont = new GeorgiaRegular();

//create a new text format object

var mainFormat:TextFormat = new TextFormat();

mainFormat.size = 18;

mainFormat.leading = 4.5;

mainFormat.font = mainFont.fontName;

mainFormat.kerning = true;

//create text field copy

var mainTxt:TextField = new TextField;

mainTxt.x = 307;

mainTxt.y = 182;

mainTxt.width = 221;

mainTxt.height = 333;

mainTxt.multiline = true;

mainTxt.wordWrap = true;

mainTxt.defaultTextFormat = mainFormat;

mainTxt.autoSize = TextFieldAutoSize.LEFT;

mainTxt.embedFonts = true;

//create a URLLoader object

var textLoad:URLLoader = new URLLoader;

//create a new URLRequest

var darkReq:URLRequest = new URLRequest ("text/dark.txt");

var invertReq:URLRequest = new URLRequest ("text/invert.txt");

var overReq:URLRequest = new URLRequest ("text/over.txt");

var screenReq:URLRequest = new URLRequest ("text/screen.txt");

var subReq:URLRequest = new URLRequest ("text/sub.txt");

//test to see that the external file has completely loaded

//once it has executed the function that will add the loaded content

//to our dynamic text field

textLoad.addEventListener(Event.COMPLETE, textComplete);

//function to execute once the external data is loaded;

//adds the external file data (the actual text) to our text field

function textComplete(event:Event):void

{

    mainTxt.text = event.target.data;

}

//create a new shape object

var sq:Shape = new Shape();

//use the lineStyle method of the graphics object to

//set the line thickness and color

sq.graphics.lineStyle(2, 0x000000);

//use the beginFill method to fill the shape

//with the specified color

sq.graphics.beginFill(0xFF86600);

//use the drawRect method to draw a rectangle

sq.graphics.drawRect(175, 100, 100, 100);

//use the endFill method to end the fill of the shape

sq.graphics.endFill();

//add our shaped to the display list

addChild(sq);

//create a new shape object

var circ:Shape = new Shape();

//use the lineStyle method of the graphics object to

//set the line thickness adn color

circ.graphics.lineStyle(2, 0x000000);

//use the beginFill method to fill the shape

//with the specified color

circ.graphics.beginFill(0xFF9900);

//use the drawCircle method to draw a circle

    circ.graphics.drawCircle(150, 150, 85);

//use the endFill method to end the fill of the shape

circ.graphics.endFill();

//add our shape to the display list

addChild(circ);

//apply a blend mode to the circle

circ.blendMode = BlendMode.MULTIPLY;

//create a display object container

var contentContainer:Sprite = new Sprite;

addChild(contentContainer);

contentContainer.x = 10;

contentContainer.y = 24;

contentContainer.width = 1000;

contentContainer.height = 725;

//set initial page

contentContainer.addChild(mainTxt);

textLoad.load(darkReq);