Hello i want to make a game (this forum i taught was the best for the thread)
I want to make rooms like this
ps.: i want to know how i can make bloody textures like this and the room enviorment
THX lixpoxx 
Step one : Learn to model
Step two : Learn to texture
will the blood be static or dynamic? For static, google for “blood brush for photoshop” and there you go.
First you need to make the textures and models you will use to build your world up with, make several modular wall sections, make some window models, different props, doors and things like that. Make them all separate. Now import them all into Unity and have fun putting them all together until you have what you want, once you like it you’ll want to put various lighting in your scene then bake a light map.