Update Mosquito Broker for new Cerbo GX Firmware

Hi, kinda new to Home assistant, but I followed this great guide on YouTube to get my Cerbo GX talking to home assistant, but due to the new security setting I have to log in by setting up my broker with a password. I cant for the life of me figure out how to do this. I need to add this info to my MQQT config file, but cant fingure out where to add it, or where the configuration file is.

mqtt:
broker: “mqtt.victronenergy.com” # Victron VRM broker
port: 8883 # TLS/SSL encrypted port
username: “any” # Username for VRM
password: “<your_vrm_password>” # Use your VRM password
tls: true # Enable TLS encryption
tls_insecure: true # Disable certificate validation (if using self-signed certs)

How are you running your MQTT broker?

Via a Home Assistant on a Raspberry Pi