Looking for Basic Data Domain Replication Instructions

Hello,

Over a year ago we had two data domain appliances installed in two different sites with one mtree replicating to another.  Now we would like to create another mtree to replicate in the opposite direction.

This seems like it should be an overly simple process, but I'm getting an error if I have the mtrees created or if their not created.

Is there just a repository of simple instructions on this?  All I can find are white papers on the technology used behind the replication.

Thanks in advance.