For example, I can’t figure out any way to texture the floor. I mean which type of texture is perfect for floors of sci-fi facilities ? Is there any other way to make it look like a sci-fi corridor ? I also need some better ways to light it or add realism or any such detail. Please let me know.
It is more about geometry than texture. And important take watch over the measurments. Your stairs size far of realism.
Take a look here, but you have to learn the basics, like bevel, bool, knife and modifiers:
I am not asking how to do it but I am asking for some ideas to improve it. Oh and by the way, how the size of the stairs should be ? The environment is a containment zone of anomalous objects(SCPs) so I want it to make it look like more of earth than in like a spaceship.
You get an scifi look with panels, integrated lights, parts which you cant say what purpose they have. Also Wire / service tunnels entries. To improve this you can label the environment with technical labels. You can use textures for warning labels, like black / yellow marked areas. Also level signs on the doors and walls. But dont use it to excessive. For the labels you would use textures, also you can use texture for panels if they are not to much extruded.
For the tutorial it is not only usage for a spaceship, the dark windows can be used for look into space, but they can also be windows to labor rooms or prison cells of aliens in a underground science facilitiy.
For the stairs, if i imagine the entry is around 2.5 meters, your steps look like .3m high, which is the double of a normal step.
For you scene i would go with light integrated in the bottom of the walls. If you dont want use a lot of panels paint direction markers on the walls, like long stripes with labels to exit, cells, labor, mess hall, etc.
Here is an example to use procedural textures.
But you have some mistakes in your scene, like overlaying geometry at the stairway, as said it goes easier if you model from start of with the right sizes, also apply scale. Otherwise operations like bevel, sizing, etc dont work as expected.