It’s basically like you’re reading a thread of YouTube comments where a conversation is being held. It’ the conversation being held in a comment section. You could look at the usernames that are provided, and imagine a random person using the username commenting, replying, or quoting a comment. For example, in this specific chain, jermlol1 had replied to ohioan1234 by copying their message and saying “nah…” and then adding their opinion to the copy.