Sanity is on the right side of your screen, which also acts as your power. Shutting the doors drains your sanity/power, but the doll on your desk allows you to generate it back. When you use the doll, there's a bar on the right side called Heat. If it hits max, your doll breaks, so try to keep the bar <70% filled. Close the door when there's someone outside the window. There's 3 things you have to keep fixed: A cube, a valve, and a breaker. You just click the cube, click the valve multiple times, and the three buttons on the breaker. There's a shark girl in the left hallway that you prevent from coming out by clicking on the button next to her door. There's also a computer on your desk that plays porn sometimes, which drains your sanity. Just click on it and it'll stop draining your sanity. Pretty easy until you hit like night 20, which is when things become more erratic. Dont know if there's a way to prevent the cowgirl chick from getting through the vents, but thats about it. Just shut doors, click objects, squish doll, click pc.
EDIT: I forgot they removed the cowgirl's mechanic entirely, so you dont even have to worry about that. I also forgot that Nile, Poppi, and Sam have different abilities: Nile will take up your entire screen, which will make you find the "wake up" button, Poppi spawns a box in your office that you just have to click and hold on, and Sam steals your doll. You can get your doll back if you find it in the camera feeds. There's only 4 doll locations as far as I know: The room with the cube towards the right, right hallway on some crates, on the small wall in the animatronic's spawn, and on the edge of a wall in Nile's Resturant.
