Simpe question about the uv editor

I am working on architectural project and i am texturing rectangular walls. When i unwrap those walls i get a square in the uv editor.
I know that i can make it rectangle like the shape of the wall but i don’t know how. Can you please tell me how?

Have you applied scale (Ctrl-A) to the object before unwrap?

Yes i did, and i still get a small rectangle in the big box area. What should i do?

if thease are rectangular walls it may be faster to use box mapping instead of uv. but if u still wanna use uv check if u used seams. if u did it properly u should already get fine shape