When she moves, she laughs
Depending on where she is, you need to close the right door (like- The door to your ->)
I don't remember what cam is needed to check if she's able to attack, but the cam is literally next to your office on the right
Another thing you can also take into account (if you wanna skip the checking on Freddy part) is the amount of laughs; 5 laughs = She will attack in the next few seconds
From then onward, everytime she laughs, you need to alternate between opening and closing the door (6th laugh = open door, 7th laugh = close door, and so on)- She pairs really well with Chica, so be aware about Chica if she appears when Freddy is not going to attack.. it gets complicated because of Chica, but following the "5th laugh" rule, you can manage Freddy with ease-