This should suffice what you need to build. Please don’t hesitate to discuss this with me if you have any doubts. We have spring in our application so we should look into integrating directly with Spring and try to keep it very light weight.
http://www.drools.org/learn/documentation.html
http://www.javacodegeeks.com/2012/02/jboss-drools-getting-started.html
http://toomuchcoding.blogspot.com/2013/01/drools-integration-with-spring-vs.html
http://mytechnorage.blogspot.com/2014/10/drools-6-integration-with-spring-mvc-4.html