I'll assume you know how to use git and have a github account (google it if you don't). I will also assume here that you are using the jBPM 5.2 installer.
1) Build the web designer:
- clone https://github.com/tsurdilo/process-designer.git (https://github.com/tsurdilo/process-designer)
- build with "mvn clean install"
- copy /target/process-designer-2.2.0-SNAPSHOT-jboss7.war to $jbpm-insatller-dir/lib/designer-2.2-jboss7.war
- in $jbpm-installer-dir/build.properties change the version of your designer war:
designer.version=2.2-jboss7
2) Build Guvnor:
- clone https://github.com/droolsjbpm/guvnor.git (https://github.com/droolsjbpm/guvnor/)
- use the 5.3.x brach - git checkout 5.3.x
- build Guvnor with "mvn clean install -Dfull -DskipTests" ....yes this will take some time to build...
- in $guvnor/guvnor-distribution-wars/target copy the AS7 war to $jbpm-installer-dir/lib/guvnor-distribution-wars-5.3.1-SNAPSHOT.war
- in $jbpm-installer-dir/lib edit your build.properties again to set the right guvnor version:
drools.guvnor.version=5.3.1-SNAPSHOT
3) Don't loose your existing stuff
- in $jbpm-installer-dir/build.properties make your jboss.clean.repository property is set to false so that the /repository directory does not get deleted (alternatively back up your process repo - export it)
4) Rebuild installer
- in $jbpm-installer-dir run:
ant clean.demo
ant install.demo.noeclipse (or ant install.demo if you want eclipse)
ant run.demo.noeclipse (or ant run.demo if you want eclipse started too)
Hope this helps.