Ok but where is the rest of chapter 3?? There has to be more?

Sorry but this is all the author posted on their pixiv
https://www.pixiv.net/en/artworks/76505192
they're the author of Watakoi / love is hard for an otaku, and their comics are usually pretty short. they're also a pretty independent mangaka, I think they were able to publish watakoi because they won a competition.