On this page of our Little Nightmares 2 guide, you will learn how to get the key in the 3rd chapter of the game. To get to it, you must find and burn one of toys.
Finding the toy
You will find the key in one of the soft toys. You can use an x-ray machine to search for it.
The key is in the teddy bear lying by the cabinet on the right side of the room.
Take it in your hands and take it to the machine.
To be sure, you can x-ray the toy. You will see the key inside.
Burning the toy
Again, take the teddy in your hands and drag it to the elevator. Note that your character doesn't have much strength, and the toy is bigger than Mono, so give him time and don't rush him.
After taking the elevator down, you will see a furnace. This is the place you need to put your toy. Six will do the same with hers to show you what it's all about.
After placing the toys in the furnace, you must pull the lever. The sound of the furnace will not attract any enemies.
Once you see that the fire has gone out, you can jump inside and take the key. With it, head to the locked door to get further.