Shadows in unreal acting weird

Do you guys have any tutorials i could follow?
I feel its hard for me to really understand how lightmaps should be layed out…
Is it just like normal uv map or should i have every thing seperated?
Also all of the walls are one model but the roof and floor is not a part of that mesh.
Maby you guys know a good tutorial that shows the correct way of doing it.
I dont know how to attach the 3d model into the forum chat :I

Here the screenshot with Alt+0
8d6e61438d293f8a220ce7fb9b33a15107843fca.jpeg

I think i already tried the method you are talking about wheres every side of the model has a planar map as seen below (Confirm/Deconfirm)
06ccc8d070838b1e5e32d80b2cdcf1f93de650db.jpeg

Or would this uv map be better (just made it)?
37334813b5ef8f3e9b4fe5688375ded4673c6cae.jpeg