Confused, and looking for MQTT Tutorial

I’m running a fresh install from APT on a Debian VM. OH3.
MQTT is working, but I need to make some changes, but am not sure of the correct configuration approach to use. I prefer textual configuration for my Items, and for Things where it makes sense to make it easier to migrate and back up.

I have Mosquitto server installed.

There are two GUI locations:
http://openhab:8080/settings/services/org.openhab.mqttbroker
http://openhab:8080/settings/things/mqtt:broker:home

And a /etc/openhab/thing file Thing configuration:

Bridge mqtt:broker:home "MQTT Mosquitto Broker" [ 
  host="xxx.xxx.xxx.xxx",
  secure=false,
  port=1883,
  qos=0,
  retain=false,
  clientid="someid",
  //certificate="",
  //certificatepin=false,
  //publickey="",
  //publickeypin=false,
  keep_alive_time=30000,
  reconnect_time=60000,
  //lastwill_message="",
  //lastwill_qos=1,
  //lastwill_topic="",
  username="xxxxxxxx",
  password="xxxxxxx"
]

Is there actually anything wrong? Textual or UI based configuration is a personal preference - one or the other isn’t wrong.