Making Grid with MovieClip. Help Please

All I want to make a grid with movieClip. But I can’t make no matter how much time I have used exploring and trying.
I have 2 movieClips and button
1 - mc_main
2 - Row
Both movieClips are linked to classes. mc_main is on stage its a small dot.
when I press button a new instance of Row should be attached to mc_main and should append. Below is code if anyone tell me how to attachieve this.
Do you have any code to share if you have done something like that to learn from it please.


package  
{
 import flash.display.MovieClip;
 import flash.events.*;
 public class Main extends MovieClip 
 {
  public function Main() 
  { 
   cmd_create.addEventListener(MouseEvent.CLICK, cmd_create_click);
  }
  
  private function cmd_create_click(evt:Event):void
  {
   var test:mc_main = new mc_main();
   test.addChild(new Row());
  }
 }
 
package  {
 import flash.display.MovieClip;
 public class Row extends MovieClip {
  public function Row() 
  { 
   trace("row");
  }
 }
 
}

package  {
 import flash.display.MovieClip;
 public class Mc_main extends MovieClip{
  public function Mc_main() 
  { 
   trace("Mc_main");
  }
 }
 
}