Thank you for your comment! The game might be a bit too hard in some places; I didn't have a lot of time for playtesting and puzzles always seem obvious to the one creating them. When I have the time, I might add some sort of hint mechanic once the voting period is over.
For the first puzzle, you need the book on the counter. Apply it to the pattern of the carpet in the other room (it's the missing pieces). The code you get will open the cabinet in the carpet room.