Need Help on making a light/sight/shadow system!

Hey Guys,
I am recently working on an isometric Zombie Survival Game for PC. And I recently tried to make the shadow/sight System so that you cant See the outsides in a room with closed door. But I dont know how to do it in UE4. I wanted to make something like they did in Project Zomboid where you got a shadow behind every tree. Screenshots for what I mean:
Hope I explainedy wish correctly
Greetings Rising
(Btw im new in the forum so I don’t know how to ask properly)