Here you go. If this doesnt work make sure the triggering volume fires your on overlap event. Looks like from your picture your using a box, if it has a static mesh it might block the player from triggering a overlap event. I used a get actor location to just add 100 to the Z axis, you could use get actor location at begin play to set a closed door position that would be called on end overlap. Also used a get all actors of class to avoid a possible bad reference.
