I covered it in-depth under this post: DO NOT use Event Tick, use Event ActorBeginOverlap - Unreal Courses / Show - GameDev.tv.
Essentially he breaks the game by using the Event Tick node because it runs every single frame instead of when an actor collides with another actor. The one you need to use is “Event ActorBeginOverlap”. The code for this is a lot simpler.