Can someone explain everything to me cause I'm just so confused 😃

Yuuma was jealous of Ataru because ataru had friends and was well liked. When he thought ataru died, he decided to take this chance to basically become him and said that Yuuma was the one that died instead of Ataru. That way, he was able to take the position of his well-liked brother and have the life he always envied his brother of having. However, at the end, it’s revealed his brother was alive all along. The sequel is from his brother’s perspective and it’s so good. I recommend it(ngl, the brother is like smarter than him in my opinion lol XD)