If you are NOT going to use Orbeon with the BPM application you can skip this step.
Orbeon is trade mark ® of http://www.orbeon.com
Orbeon is a Java application that runs on Tomcat or JBoss.
Orbeon can be installed on a Windows or Linux machine.
After the installation of Tomcat/JBoss just deploy the WAR that can be downloaded from http://www.orbeon.com
For more detailed information about Orbeon installation: http://doc.orbeon.com/installation/index.html
Any question about Orbeon installation can be asked here: http://discuss.orbeon.com/