Found it on his death (Rusame)

you have 3 more nights ~ (pt.1)

Michael/America's pov: 

Another day to work... I didn't know work can be so terrifying at first... then there is that robot girl and I think the name of the robot is Circus baby? if I'm not mistaken, well I do remember this when my dad William/Britain made this robot for my little sister Elizabeth/Canada, then the next day she's missing until now... I kinda miss her after a long period of time..

"Now that your elevator experience has been customized to your needs, and you're thoroughly relaxed, it's worth mentioning that due to your lackluster performance yesterday, your pay has been decreased by a substantial amount. Please enjoy the rest of your descent."

I- WHAT THE HELL I did my best yesterday and my pay is lowering? how dumb, oh well I got to accept that rather than I'm starving to death about now... after I reached the main control area the voice said that:

Due to unforeseen malfunctions from today's shows, your nightly duties will require you to perform maintenance that you may or may not be skilled enough to perform. It became necessary for technicians to attempt to disconnect Funtime Freddy's power module. However, they were unsuccessful. Allowing them to try again would be an inefficient path forward, as we would need to allow six to eight weeks for recovery and physical therapy. You will need to reach the Parts and Service room on the other side of Funtime Auditorium to perform the procedure yourself. Let's check on Ballora first, and make sure she's on her stage.

What? Funtime foxy? that weak robot? hah, I can pass that test if I need to go to that storage place in the end..

*After passing Funtime foxy*

okay, that was a bit scary to be sure... 

Great job reaching Parts and Service! It seems that Funtime Freddy is out of power, which should make your job much easier. The release switch for the chest cavity is located on the underside of the endoskeleton jaw. To reach it, we will first need to open the faceplates. You will need to press the face-plate release triggers in a specific order, and it's important to be as precise and as careful as possible. Locate the small button on Freddy's face, just under his right cheek, and press it.

What? you mean I need to do that? oh well *pressing the button* 

Great! Now locate the button under his left cheek, and press it.

Mk sounds easy.. 

Great! Now carefully locate and press the button next to Freddy's right eye.

done that..

Great! now carefully locate and press the button just above Freddy's nose.

*faceplates open* okay.. not that much bravery..

Good job! The face-plates should now be open. Locate and press the small button on the underside of Freddy's endoskeleton jaw

Excellent. The chest cavity should now be open. Remove the power module from the chest cavity.

(I'm gonna make pt.2 for this since it's too long tbh)