On the standby, do not create a PostgreSQL instance, but do ensure the destination data directory (and any other directories which you want PostgreSQL to use) exist and are owned by the postgres system user. Permissions must be set to 0700 (drwx------).
Check the primary database is reachable from the standby using psql:
psql 'host=node1 user=repmgr dbname=repmgr connect_timeout=2'
Note: repmgr stores connection information as libpq connection strings throughout. This documentation refers to them as conninfo strings; an alternative name is DSN (data source name). We'll use these in place of the -h hostname -d databasename -U username syntax.