Applying materials without it being stretched

Thanks, I guess I will try to watch some more tutorials. Pretty sure once I get the hang of it it will go smoother.

Question though: Am I correct in assuming I need to use BSP for walls, floors and ceilings and meshes for everything else like boxes? In that way, I guess it would be similar to using world and detail brushes in hammer, am I right? And is there anything like map leaks? Or isn’t that possible in UE4?

Yes I would very much like to start the professional way, because I care alot about optimization.

Thanks for helping me out