Well, Manga Rock is just a place where you might find Attack on Titan Junior High and other mangas. But they aren't inherently related in a special way. It's more like Manga Rock provides access to it.
I think there's no direct connection. Manga Rock is a platform for various mangas, but Attack on Titan Junior High is a specific manga series.
The connection between Manga Rock and Attack on Titan Junior High is that Manga Rock is a source where you can potentially read Attack on Titan Junior High. However, that's about it. It's not like they have some exclusive or unique bond.
Chapter 808, "Dare to Spank Him?!", is the clearest early answer because it turns Jiang Buchen's situation into a concrete plot event. It opens with I don't listen, I don't listen," Jiang Bufan once again started his...
A practical answer is Chapter 4, because it turns the idea into a concrete scene. The chapter opens with Qiao regretted her words as soon as they left her mouth., adds pressure through It's difficult for us when you ask for a guest's room number and key right..., and ends on A little girl acting.
Chapter 702, "This is One Hundred Million, Sign Here!", is the clearest early answer because it turns Wu Daoshan's situation into a concrete plot event. The chapter turns that into something concrete by moving from Bai Lu was at a loss for words.
A practical answer is Chapter 17, because it turns the idea into a concrete scene. The chapter opens with Jiang Li glanced at Jiang Shixu, who was tense and anxious behind her, and..., adds pressure through That girl who puts on makeup like a ghost deserves to be called naturally..., and ends on.
Chapter 760, "Daoist, I've Long Heard of Your Great Reputation", is the clearest early answer because it turns Long Heard's situation into a concrete plot event.
Chapter 867, "Then what does our child count as?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 780, "There's Someone in Your Room!", is the clearest early answer because it turns Was Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from Sister Li was a bit confused.
A practical answer is Chapter 17, because it turns the idea into a concrete scene. The chapter opens with Jiang Li glanced at Jiang Shixu, who was tense and anxious behind her, and..., adds pressure through That girl who puts on makeup like a ghost deserves to be called naturally..., and ends on.
Chapter 822, "The Yu Family Gave Too Much", is the clearest early answer because it turns Gave Too Much's situation into a concrete plot event. Early on, Jiang Li entered the reception hall, which was already quite crowded..
Chapter 816, "Don't Take Them Seriously", is the clearest early answer because it turns Mom's situation into a concrete plot event. The setup is Unexpectedly, they didn't cry or fuss;