Dev setup instructions?

Hi!
Thank you for working on this.
I want to write a game in ClojureScript, and was using BabylonJS directly till I stumbled upon this project.
I would love to take it for a spin/update it/etc but can't understand how to get started.
Could you add setup instructions to the README?
How do I run the tictactoe game, for example?
How do I start off with a new game?
How do I get a working REPL?