Hello
Without further ado, here is the screenshot
Yeah, it looks totally bare
Any help is appreciated
I would suggest inserting a ColorCorrection effect into the lighting and adjusting saturation and contrast to your liking.
Add little dark grey lines to the bottom of the walls, and make the non-metal stairs and stuff concrete material. That should start you off
Add some more detail to those beams supporting the second floor, You can also make the floor tile or another kind of floor pattern, On the ceiling add pips or beams for support and detail, On the walls, you can make fake doors leading nowhere, If its a Lab maybe change the colors up a bit using diamond plate and neon lights can help, or maybe you can add lab desks. Either way these are some ideas anything you want to add is 100% up to you! Good luck on your build. 
How?
Yes, thank you very much, these will do
If you’re still looking for textures, I use this site. They have a ton of free seamless textures.
thanks, I will use this someday. no sarcasm intended 
Unrelated, but an updated photo with added beams and floor texture, what do you think?
The new beams look awesome!
The floor looks nice as well. I personally would try adjusting the transparency so it’s more dark gray than black. But that’s just my opinion :). It looks really good as is!!
may I ask i this is a SCP game? and if you used a reference for your build
Its supposed to be a horror/murder mystery game
I didnt use a reference, this is all from my brain
then, try using references, it will greatly improve the build. Of course, you don’t need to change the build, just use references for the lighting and ideas for decoration.
Looks a lot better man keep up the good work!
Looks a lot better than the first screenshot, got notifications from this and wanted to take a look.
Thanks, the only thing left to do is just add doors, and then ill be done.
