How to make Simple Event Triggers?

i wanted to make simple event triggers in one of the condition:
Event 1: When the player walk through some point, there will be a static mesh and disappear when the player rotate the camera backwards to the static mesh.
Event 2: Player walk through some point (like doors), Lights will turned off and after some time it will come back on

Could someone point me to some tutorials which i haven’t find them, or guide me in making the blueprint, because i’m still very beginner in visual scripting in UE4…

Thank You!