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 version or the zip version.
- watch the introductory youtube video detailing the system as a whole
- watch the mutator walkthrough video that guides you through a mutator and how it's intended to be interpreted
For more details in depth, you can read the Wiki