to get all the endings you need to do the following to get all the endings

While you take control of Levin before taking the key, save the game then take the key

when you take control of Aria, interact with the door, don't go through the door

continue playing in the Library no matter what options you choose when the Normal Ending screen appears press F12

load the record where you haven't taken the key yet

when you take control of Aria, interact with the door, then enter the room and take the photo

tell Levin you entered the room

do not read the letter before starting Chapter Final

during the conversation like Clyde will ask you select the third option "Both libraries"

save the game before climbing the ladder then during the conversation with Clyde select option 2 "Broken"

while Clyde asks you one last question, select the first option "I'd change it" then continue the game until you reach Perfect Ending

load the record before climbing the ladder then select the first option "Followed"

while Clyde will ask you the last question, select the second option "I wouldn's change it" then continue the game until you reach the True Ending ending, i.e. when Aria's Story appears on the screen

load the record where you haven't taken the key yet

when you take control of Aria, interact with the door, then enter the room and take the photo

tell Levin you didn't enter the room

do not read the letter before starting Chapter Final

during the conversation like Clyde will ask you select the third option "Both libraries"

load the record before climbing the ladder then select the first option "Followed"

while Clyde will ask you the last question, choose the second option "I wouldn's change it"

after talking to the books before entering the location where the last scene is to appear, save the game before selecting the option

select option 2 "I don't accept it." then keep picking as you will do Bad Ending 2

load the save before entering the last location

select 1 option "I accept it." continue to blacken you will do a good ending when the screen turns black then Lewin finds Wendy in the forest