Targeting a nested symbol's timeline?

Hello, I'm new to Edge, Javascript and HTML5 (coming from Director/Flash/After Effects background) I'm wondering if there's a way to target a nested symbol from a button. I would like to make a simple Pause/Play toggle button that stops a nested symbol is it's playing and plays it if is stopped. In software's I'm familitar with, this can be done with a simple target path and  if/else conditional statement, but I can't find any examples that don't seem much more complicated. If you don't mind, could you please be specific as to where the code goes, as I'm new to this and don't yet have a grasp of the file structure? Thank you very much, I really appreciate your help