Animation Blending

I’m looking for an example of or a source text file of a .state_machine file that has multiple animation layers/nested animation layers (I think), as well as, how to transition between these layers and it’s child states.
What I am trying to do is have multiple animation events to be able to played/triggered at the same time such that if a character mesh is in the walking loop it can also trigger an event to perform actions with arms and upper torso.