This tutorial assumes you have already read Multiplayer tutorial 1: Concepts . The easiest introduction to the multiplayer object in Construct is a simple chat...
You can make whatever content you like with Construct. However due to moderation problems, chat rooms are not allowed in the Construct Arcade. You can however publish chat rooms anywhere else.
Would making a chatroom based game be allowed. For example, its not an actual chatroom but more of a story game based in a chatroom.