Eclipse (with maven) :
Downlod the project to your workspace, and import the project as "existing projects into workspace". Then run unit tests to see that the project is set up correctly
In case that doesn't work or you're not usign eclipse you can instead checkout the tag without-eclipse : git checkout without-eclipse. Then import as "existing maven project".
Eclipse (without maven)
* cd *workspace*
* unzip gameoflife.zip
* Eclipse : File -> new -> java project -> enter coderetreatjava -> press finish