Actionscript 3 :: How To Update Children

For starters let me just say that I am very new to action script and also that I'm not using adobe creative suite, I am using notepad with flex as a compiler. I have two classes, a main class and a class called OBJECT_square.

Here is the MAIN class:

package
{
import flash.display.*; import mx.core.*;
import flash.events.*; import mx.collections.*;
import flash.geom.*; import mx.controls.*;

[code]...

Now my problem is this. Simply put I would like the square that OBJECT_square draws to move right when I press the right arrow key. Right now I can only get it to be drawn once (though I am actually creating two separate squares in two different spots). Now the thing I need to know is if I have used the keyboard event correctly in OBJECT_square. I used keyboard event in the main class as well to display the last key I pressed but I'm not sure how to use it in a class other than the main one. Also I'm not sure how to 'update' the square so that it is redrawn when it moves, that is remove its old self from the display list and reinsert its new self. The whole kinda point to the code is that the square be 'self-sufficient', ie contains all the code needed to draw it and move it rather than relying on any other class. I basically want it so that once another class has made a square the square is capable of doing everything else on its own.