ActionScript 3.0 :: How To Add Button To Dynamic Text File

I am trying to load different .txt files on the screen with each button click. I am in my first flash class and have only grasped a little bit of actionscript.

Code:
the button names are: bberk_btn apost_btn phales_btn
the text file names are: bberk.txt apost.txt phales.txt
How to connect the text files to the function of each button
var content_req1:URLRequest = new URLRequest("text/hales.txt");
var content_ldr:URLLoader = new URLLoader(content_req1);
content_ldr.addEventListener(Event.COM... onComplete1);
function onComplete1(event:Event):void {about_txt.htmlText = event.target.data;
[Code] .....