To expand on this some, if you need to setup a cluster then you will want to setup your load balancer (per the Process Automation documentation) and run a reinstall of 4.3 SP01 to set up this orchestrator correctly as a cluster member.
If you have any patches on top of 4.3 SP01, those will need to be reinstalled afterwards as well.
From there you can follow the documentation for installing a cluster node for the domain orchestrator, and at this point will have a working 2 node Process Automation cluster setup.
~Jennifer