Open a terminal and cd to the directory you unarchived:
cd <the directory you just unarchived>
Within it you'll find:
koans: this directory contains the application and its lessons, it is all that is needed to advance through the koans themselves and it can be distributed independently
lib: this directory contains the code the koans engine is comprised of and built with
gradle: wrapper for build library used to build koans source, setup project files in eclipse/idea, run tests, etc. you probably don't need to touch anything in here
Change directory to the koans directory: cd koans
If you are using windows enter: run.bat or ./run.sh if you are using Mac or Linux
Developing a Koan:
Follow any of the existing koans as an example to create a new class with koan methods (indicated by the @Koan annotation, they're public and specify no arguments)
Define the order the koan suite (if it's new) will run in the koans/app/config/PathToEnlightenment.xml file
Optionally you may use dynamic content in your lesson, examples are located in the XmlVariableInjector class (and Test) and the AboutKoans.java file
Something's wrong:
If the koans app is constantly timing out compiling a koan, your computer may be too slow to compile the koan classes with the default timeout value. Update the compile_timeout_in_ms property in koans/app/config/config.properties with a larger value and try again.
