How you setup it up and now it works depends on if you are using Oracle Documaker Enterprise Edition (ODEE) or Oracle Documaker Standard Edition (ODSE) as this is one of a number of places that the two editions differ greatly in the way you configure them.
With ODEE your primary setup for the batch is done in the Documaker Administrator web app under the Assembly Line where you get a list of batches defined and you can make new ones. The configuration fields and values have mouse hover text explanations of their purpose. Generally the transaction's recipients are filtered into each batch by the selection criteria and you can define the type of batch (scheduled or immediate) the output type, the order, the pre/post batch and tran DAL, callback, batch break, the post-batching processes to run on each batch (Archive, Notify, Publish), etc.
You can use some ODSE type batching rules to futher control the filtering by ODEE batch by name grouping association defined in the ODEE batch configuration for more generic filtering.
With ODSE it is primarily done via MRL, INI and JDT configuration on how to batch, e.g. batch by recipient type, by recipient, etc. I am sure there is documentation on ODSE batching options.