Sending a message from PC to the mangOH through MQTT communication?

Hi guys,
can someone explain to me how can I do to send a message from the Ubuntu PC to the mangOH Green with a MQTT communication?
I want that my broker is Mosquitto MQTT (I have already installed it on Ubuntu). I want to see if I can send/receive messages from Ubuntu and mangOH. Have I to install mqttClient app (from mangOH project in github) on my mangOH? And how can I set the Mosquitto broker?

In other words, on ubuntu I successfully did:

I want to understand if is possible to do the same thing between PC and mangOH using Mosquitto
I apologize for the inconvenience

Can you help me? Please? Have I to use the mqttClient and lounch it on the board?