First set the configuration options in
wal_level = logical
The other required settings have default values that are sufficient for a basic setup.
pg_hba.conf needs to be adjusted to allow replication (the values here depend on your actual network configuration and user you want to use for connecting):
host all repuser 0.0.0.0/0 md5
Then on the publisher database:
CREATE PUBLICATION mypub FOR TABLE users, departments;
And on the subscriber database:
CREATE SUBSCRIPTION mysub CONNECTION 'dbname=foo host=bar user=repuser' PUBLICATION mypub;
The above will start the replication process, which synchronizes the initial table contents of the tables
departments and then starts replicating incremental changes to those tables.