Mu Ren Zhuang is an exercise form to practice Code Flexibility - something I have not seen before.
If you want to get doing immediately, you can
- download the latest release, choose either the [tar] 3 version or the [zip] 4 version.
- watch the [introductory youtube video] 2 detailing the system as a whole
- watch the [mutator walkthrough video] 5 that guides you through a mutator and how it's intended to be interpreted
For more details in depth, you can read the [Wiki] 1