Here is a useful story breakdown and guide regarding this manga, as you likely won't find it on mainstream platforms due to its mature nature.
I notice you're asking for a specific manga chapter ("shounen ga otona capítulo 1 para leer" — Shounen ga Otona means something like "The Boy Becomes an Adult"). However, I don't have access to or the ability to reproduce copyrighted manga text. shounen+ga+otona+capitulo+1+para+leer
Debido a que no hay una licencia oficial en español (a la fecha de este artículo), grupos de scanlation como Shuumatsu no Scan o Ivrea Fansub han traducido Shounen ga Otona . , busca en: Here is a useful story breakdown and guide
: (Check for official availability depending on your territory). Debido a que no hay una licencia oficial
For "Shounen Ga Otona," if it's a lesser-known or indie title, you might need to look into more specialized platforms or directly search for the author's official website or social media, where they might post updates or links to their work.