Problems on looping entire timeline

Hi everyone!

I am a newbie on Animate and I encounter a problems on looping the entire timeline when create my html 5 banner with online tutorials.

I have total of 3 scene in the banner.

I imported all the element from Illustrator, and named the layer with “S1” “S2” and “S3” .
I animate the elements inside each layer.

When I finished the animation, I added a new layer call “coding” and add the action:
if (!this.looped) this.looped = 1;
if (this.looped++ == 3) this.stop();

But it just keep looping Scene 3 after playing the banner once, instead of looping the whole timeline.
And it didn’t stop when it play 3 times.

I try to use gotoAndPlay(X) instead, but I cannot stop looping suscessfully.

It would be great if anyone can give me a helping hand. Thank you so much!