Hot to trigger overlap event in Unreal Engine 4.15

I saw a tutorial on the net about how to use trigger boxer, but, there are a few differences between what it is said there, and what happens in my case.
There you can see this kind of event box

While I have this kind of box, doing the exact same steps

There is something new there, an overlaped actor variable, I do not understand why.
Can somebody help me? What I want, is that when the player runs in the trigger box, an object to be moved.(the object is moving when using the Event tick

That is what the overlapped actor is. When your player enters the area, that event fires passing your character as the overlapped actor. If you have AI moving in the world you should cast it to you player BP to make sure only the player can move the object.

Hope this helps