I believe the application has been completely developed using the web ui. Personally I would recommend using web designer to work on your knowledge assets such as processes and rules. Embed them in knowledge archives (aka projects in kie-wb) and define dependencies to the project for any code it requires to run. Such project is then deployable to execution environment. Take a look at the deployment options described here which might be of some help.
bmozaffa recently released Reference Architecture: Business Process Management with Red Hat JBoss BPMS Suite 6 but you'll need an account to access it. See Section 5.
"This reference architecture reviews Red Hat JBoss BPM Suite (BPMS) 6 and walks through the design, implementation and deployment of a sample BPM application. Various features are showcased and a thorough description is provided at each step, while citing the rationale and explaining the alternatives at each decision juncture, when applicable."