First of all, download a version of the webapp from
Download also, the sources of the core.
Download the project for Netbeans if you want to modify the sources. Even if you use a different IDE, like Eclipse, downloading the Netbeans project would be better than downloading only the sources because you will get all the necessary files and libraries to build the webapp and generate a war file.
Remember to create a jfw.properties file and save it in a directory. The directory must be included in the classpath.
You can find examples of jfw.properties in the webapps or here.
In the next pages we will see in detail how to: