Right way to set up a secondary citus worker

I am experimenting with the postgres-addon citus. So far I have setup a cluster with one coordinator and three worker nodes. Now I want to setup a secondary for one of the worker nodes. So far I have setup streaming replication from that worker node to the fourth (standby) node. Do I have to add the standby node as secodary now with add_node and noderole "secondary"? **citus_add_secondary_node** is better, since you have to define the suiting *primary* node with that command? Or is it simply enough to setup a fresh database with citus extension and the *add_node/secondary* will turn that node into a secondary with all the data from the worker? I get the right group-id for the secondary with this command: select * from pg_dist_node;