You should be able to set up an event notification and do it that way
Or as it first person a simpler way would be just to check I the player is moving by using the vector length and velocity nodes.
Then just use a branch . If the player is moving then use the playsound at actor location node or if he is not moving do nothing.
I can try and upload a screenshot later
Or in the meantime you could also try this method
Tesla channel is awesome
Footstep tutorial