BDR management is primarily accomplished via SQL-callable functions. Functions intended for direct use by the end user are documented here.
All functions in BDR are exposed in the bdr schema. Unless you put this on your search_path you'll need to schema-qualify their names.
Do not directly call functions with the prefix internal, they are intended for BDR's internal use only and may lack sanity checks present in the public-facing functions and could break your replication setup. Stick to using the functions documented here, others are subject to change without notice.