Arduino YUN and Raspberry on MQTT

Hello, I'm aproaching to Arduino World, and I'd like to create the following architecture: arduino YUN get data from sensor,and send it,on wireless communication, to raspberry Pi.
I connected YUN and Raspberry on the same network, from raspberry i can ping arduino.

In internet i found the MQTT protocol that seems good for my design, but i have difficulties to write a sketch for wireless YUN, and I don't know how to check if i'm receiveing correctyl data on raspberry.

Someone can help me?? :frowning:

If you are a beinner, leave MQTT for later reflection and start with basic stuff, e.g.