Chronologically, Chapter 23 is the earliest moment. Chapter 23 notice that her nails are pink, not black. This is when they start dating and he gave her the bonnet.
From Chapter 23 to 30, they are dating for the first time.
Chapter 31, she got into an accident and lost her memories of them dating. From 31 to 40 it's them falling in love again and start dating, but she still doesn't remember the past.
Chapter 41 is the night before Chapter 1.
Chapters 1 to 22 is their date all the way up to her cosplaying a cop and getting all yandere over the delivery person. Chapter 42 chronologically comes after chapter 22.
The Manga he buys during the early chapters was drawn by her. The person he went to the arcade with was her. Ayase on Discord was her old account. Granted... these are major plotholes right there, given that she would be getting paid for the manga sales... but whatever.
I assume that she stabbed him (she has a knife in her hand) or was about to stab him and got her memories back.
tl;dr:
Chronological Order -> Chapters 23 to 41 -> Chapters 1 to 22 -> Chapter 42
Basically...
Present -> Chapters 1 to 22 and 42
Flashback -> Chapters 23 to 41