The first step in deploying AquaLogic BPM to a cluster is to create a domain that has multiple managed servers and at least one cluster. You can create this domain using the WebLogic Server Configuration Wizard. This wizard is part of the basic WLS installation and allows you to easily create a domain with multiple managed servers and clusters.
See Creating WebLogic Domains Using the Configuration Wizard for information on creating WebLogic Server domains and using the Configuration Wizard.