How to refer to timeline of createChildSymbol

I am adding a symbol (symbolToBeAddedFromLIbrary) into a container element (containerHolder) that is living inside a symbol on the stage (containerHolder)

var myNewChildSymbol = sym.createChildSymbol('symbolToBeAdded', sym.getSymbol('containerHolder').$('container')

"symbolToBeAddedFromLIbrary" has a timeline with labels tile1, tile2, etc

I want to click on an arrow symbol (sym.$('arrow') on the stage and advance myNewChildSymbol to the next label

My understanding is that I when I use createChildSymbol(), I must specify an element (as opposed to a symbol).

I am not understanding how to then access the timeline of the symbol that I added. What I am trying to do is this (but it does not work)

sym.getSymbol('containerHolder').getSymbol('container').getSymbol('myC hildSymbol').stop('label');

container is NOT  A SYMBOL so I can't really do this. What then?