Hey MD,
Sounds like you're getting there. Please take a look at the snippets in the Actions panel under Playback and the Adobe Edge Animate CC JavaScript API I mentioned previously for examples on how to use play and stop methods.
To stop playback in general, use:
sym.stop();
To stop at a certain time/label, use:
sym.stop(3000);
or
sym.stop("myLabel");
Remove all triggers that have incorrect code such as stop(), etc. as they will bung up the rest of the code. You must preface these methods with sym. After you call sym.stop(), your timeline won't play again until you call sym.play().
hth,
Joe