how to add multiple controllers to home assistant? by MQTT

[Gooogle]

How to describe configuration.yaml
I have two controllers KC868H32B version 4.20


mqtt:
  broker: 192.168.0.10    #home assistant IP
  port: 1883                   #Port
  username: abc # first controller
  password: 123

                        # how to add second or the third controller? 

And how to add severals controllers to Mosquitto broker configuration?