You don’t.
The intention of the GH repos is to debug, improve and enhance this website, not to use it on your own host.
As you will quickly find out, everything the repos holds are a few examples and none of the proper missions.
That has a good reason(You know, noobs trying to get the answers that way). :D
It is also not a script, it is called a web application. (Note the use of PHP)
You can put everything in the right place and configure everything by hand by simply reading either one of the *.sh files.
If you don’t succeed: Google.