All solutions are from my playthrough and experiences may change, if your playthrough does not match comment why and I will edit
*** Spoiler - click to reveal ***Start the chapter off arriving at the batcave
Alfred has been fatigued
Check both of the central cells on the batcomputer, send data to Avesta
Go upstairs with Alfred, to meet Tiffany
Tiffany pitches her new DC movie, then a gun
John texts you if you choose to trust him that he found Harley
Arrive at the carnival, Interact with a few items, then the hallway will light up. Enter
WARNING Jumpscareish thing (It got me at least) Down the hallway
Have a chat with John, QTEs will follow
John will ask you if you believe him or still dont trust him
End of Chapter