So you came across SCP-087 while exploring... or while running from another SCP. First off, you need a level 2 card, which you can get in the starting room, on a chair to the right side of the platform. (Right when you are in front of the stage. it would be on the left if you were ON the stage).

Yes, there are randomly generated items on the staircase. I am unsure if having a light will make a difference, but when I went down, I didn't have one. Mentioning this because, if it does (which I doubt) it might make seeing the items easier. I booted up the same save game, got a light and went back. It does help quite a bit actually. The items I've found so far are: documents(From SCP-### to those titled ones like Sad wrap, how much water is enough water, etc), Food and water (Apple, Beans and water), Keycards (Guest pass, VIP pass, tech pass, level 3 keycard, level 4 keycard, level 5 keycard) , bandages, ammo(5mm, 9mm, shotgun shells), gun attachments/clips(M4A1 stock, P1911 clip), guns(M4A1 and P1911) a flashlight and a cloth backpack, leather backpack

Ok, now its time to go down the stairs. It is pretty easy, just walk forward. Occasionally you will encounter a humanoid with the smile that you may have seen on a loading screen. I don't know if that is supposed to be SCP-087-1 as SCP-087-1's description is literally "... which appears as a face with no visible pupils, nostrils, or mouth." yet this has a body, head, eyes and mouth.... If you encounter this entity, fret not, as it just hinders your descent for a bit... As for how far it goes down... I've been going down for an hour... Just the entity becomes more frequent, and "rarer" loot.