The Homebrew package manager includes launchctl plists to start automatically. For more information
run brew info postgres.
Start manually:
pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start
Stop manually:
pg_ctl -D /usr/local/var/postgres stop -s -m fast
Also, To login for the first time -
sudo -u kamal psql postgres
where kamal is superadmin and postgres is default DB name