How to select element from Library ( Code )

I want to play an element from the Stage - and when it has finished add another symbol from the library ( to the Stage and play it / remove the one that was on the stage )

Problem is that I don't know how to select items from the library . I have tried

var all = sym.$('*');

console.log(sym, all);

but it selects only items from the Stage.

Thanks!