Personally purchased and uploaded translation: https://www.dlsite.com/maniax/work/=/product_id/RJ01515906.html
@Geoff asked twice in the comments below when an English version would be available, so I guess I'll just bite the bullet and translate it.
Since I haven't actually experienced this work myself, please forgive me if the translation isn't perfectly accurate. If you find any errors, I'd really appreciate your feedback and bug reports so I can improve the quality of the machine translation.
Part 1:
English AI translation：https://e-hentai.org/g/3983212/c47fd4da60/

Japanese：https://e-hentai.org/g/3803449/0d08c8396d/

Chinese AI translation：https://e-hentai.org/g/3976940/04cd036692/

Part 2:
English AI translation: https://e-hentai.org/g/3983241/fb80102bd6/

Original Japanese: https://e-hentai.org/g/3977114/f61dfba532/

Chinese AI translation：https://e-hentai.org/g/3977233/9a32dc5858/

Side Story-Side Story - Secret After-School Lessons：
English AI translation：https://e-hentai.org/g/3983485/756790e67f/

Japanese：https://e-hentai.org/g/3977461/21437472c1/

Chinese AI translation：https://e-hentai.org/g/3977785/4dabf4facb/

Part 3:
English AI translation：https://e-hentai.org/g/3983603/805ababe8b/ （You are here.）

Japanese：https://e-hentai.org/g/3977298/c047c1c6ef/

Chinese AI translation：https://e-hentai.org/g/3977318/e2c74d6d46/