assign a action/function to a button

Hi.

I have followed David Torno's extendscript series.

I can't seem to figure out something as simple as assigning a action  to my button.

the button is in the res variable.

//  res = "group {orientation; 'row',\

                groupOne: Group{orientation: 'column',\

                MinButton: Button{text: 'knap'},\

},\

}";

myPanel.grp= myPanel (res);

//

How do I add this code to the button,which basically add a new comp to the project window.

//

app.project.items.addComp("newComp", 1920,1080, 1

0, 10, 25);

//

Regards HRB