Info gathered from IRC discussion with tsurdilo:
1) install git and maven
2) git clone https://github.com/bpmc/bpm-console.git
3) mvn clean install -Dconsole.profile=jbpm -Dfull -DskipTests
4) mvn eclipse:eclipse
5) git clone https://github.com/droolsjbpm/jbpm.git
6) mvn clean install -Dfull -DskipTests
7) open eclipse, import projects.
8) search pom files in jbpm for "<version>2.3.4.Final</version>" and replace with "<version>2.4.0-SNAPSHOT</version>". This tells to use local version
9) change bpm-console code -> compile console code -> compile jbpm code
10)after that go to your $jbpm/jbpm-distribution/target dir
there you will find the distro zips you just built
11) copy jbpm-5.3.0-SNAPSHOT-bin.zip and jbpm-5.3.0-SNAPSHOT-gwt-console.zip from $jbpm/jbpm-distribution/target dir
to $installer-dir$/lib directory
12) now your installer (if you have 5.2 is not going to use jbpm 5.3.0..itll be on 5.2.0
so in this step edit $installer-dir$/build.properties and make sure you update your jbpm version to jBPM.version=5.3.0-SNAPSHOT
Also you need to add to $install-dir$\db\persistence.xml following entities
<class>org.jbpm.process.audit.ProcessInstanceLog</class>
<class>org.jbpm.process.audit.NodeInstanceLog</class>
<class>org.jbpm.process.audit.VariableInstanceLog</class>
6) in $installer-dir$ run:
ant clean.demo
ant install.demo (or ant install.demo.noeclipse if you dont want eclipse)
ant start.demo (or ant start.demo.noeclipse if you dont want eclipse)