VPDA is built and managed using maven. If you use maven for your project, then integration of vpda is very easy. You can use maven repository http://vpda.org/maven-repo and use vpda as any artifact dependency. You can find groupId and artifactId in project summary for each module. If you do not use maven, you must compile versus packaged jars in distribution zip file in dist/modules folder.
After downloading distribution zip file there is src folder. This is root source folder with main project pom and all submodules.
If u want just to build without distribution zip, issue maven command
mvn clean install -Dvpda.repos