AS2 to AS3

Hi, I have designed a flash demo for one of my client using AS2 commands like
gotoAndPlay(“start”);
parent.stop();
gotoAndStop(12);
stop();

But suddenly he wants the demo to be converted in AS3 and when I publish the demo in AS3 it is giving many script errors…

Can anyone help me by sharing few tutorial links or by sharing the basic commands of AS3.