I don't really understand what d oyou mean by 'implement'? Those functios are already implemented so you can call them like any other function functionName();
The difference it that function body is in super class insted of your extended class.
If you wanna to change function behaviour or add some functionality you can override super class function
public override function functionName():void
//you can writhe new code here
//you also can run this function from superclass super.functionName();