Hi pryelluw! There's no ready to use development environment. There are scripts to build a toolchain, and scripts to build the system, but beyond those things, everyone sets up their own environment they way they like. :)

It usually takes less than 30 minutes to have everything set up if you're on a modern Linux system. Build instructions can be found here: https://github.com/SerenityOS/serenity/blob/master/Documenta...