PGBouncer help (how to get it working)

I had pgbouncer working somehow, but we have switched servers recently
and now I cannot for the life of me figure out again how to set it up.

Online guides say things  like "create a user ID". Well, where? Inside
PG the database? Or in my CentOS system?

Here's my "/etc/pgbouncer.ini":

    [databases]
    * = port = 5432

    [pgbouncer]
    listen_port = 6543
    listen_addr = 127.0.0.1
    auth_type = trust
    auth_file = /var/lib/pgsql/pgbouncer.txt
    logfile = pgbouncer.log
    pidfile = pgbouncer.pid
    admin_users = postgres,MYSITE_pgbouncer
    pool_mode = transaction
    server_reset_query = DISCARD ALL;
    server_check_query = select 1
    server_check_delay = 10
    max_client_conn = 1000
    default_pool_size = 20
    log_connections = 0
    log_disconnections = 0
    log_pooler_errors = 1


And here's my authfile, "/var/lib/pgsql/pgbouncer.txt" --

    "MYSITE_pgbouncer" ""

Is there something else I need to do? What steps am I missing? When I
start pgbouncer at the command line, I see this error:

   WARNING: password file "/root/.pgpass" has group or world access;
   permissions should be u=rw (0600) or less
   psql: ERROR:  No such user: MYSITE_pgbouncer

Thanks for any tips!