The first monster is just in the beginning!

[BrooksyFC]

He's basically saying that in the Old Archives, if you try to proceed without picking up the lantern, you'll notice that the door is locked.
Now, if you go back and pick up the lantern, you'll hear a monster opening the door.

Has anyone checked it out?

Thanks for clearing that up haha. I'm gunna check it out tomorrow night at my mates