That's the project web page. Inside that page you can find the project repository URL. Github host projects using GIT, its like SVN or CVS. You need to install GIT first and then run:
git clone git://github.com/Salaboy/emergency-service-drools-app.git
That will checkout the application source code to your machine. After that, following the instructions in the README file you can compile and run the application.
Alternatively you can browse the source code from the link that you paste. Take a look at here:
https://github.com/Salaboy/emergency-service-drools-app/blob/master/emergency-service-app/src/test/java/com/wordpress/salaboy/BasicProcessTest.java
That test shows how the application can interact with the Emergency Service Business Process.
Hope it helps.
Greetings