The lever is only for 1 of the mannequins (or whatever the are). The other one that keeps roaming on you requires a different approach. It's a bit more of a pain in the ass depending on where you are but when the timer and skull on the top corner shows up, you actually have to go back to your office (where you start the night) and grab a hard drive, they're on the right of your computer, then run back to the room with the lever and across from it is a console the hard drive goes in. The slots are on the bottom right I think.
The game has a bunch of potential and I anticipate it's future, but it definitely need some more clarity in your tasks, and a way to view the hints at will instead of a random one after each night.