>> For Instance, you don't have the tree structure on the left << This is a change in the Guvnor navigation that happened recently. You can still click on "Create New" and create a new workitem definition config.
In order to user Guvnor 5.3.x you would need to update your jBPM console as well.
1) Build jBPM from master (mvn clean install -Dfull -DskipTests)
2) copy the created jbpm-5.2.0-SNAPSHOT-gwt-console.zip your $jbpm-intaller/lib directory (delete old one)
3) copy the created jbpm-5.2.0-SNAPSHOT-bin.zip to your $jbpm-installer/lib directory (delete old one)
4) update jBPM.version in $jbpm-installer/build.properties directory
5) run "ant clean.demo", "ant install.demo", and "ant run.demo"
Hope this helps.