MQTT Issue

[aa7401]

I was working on the Lab 1 from Week 2, and I hit an issue when I reached the 7.2 API Team chapter of the worksheet. Basically, I tried building the MQTT server with regards to the tutorials that were provided, but the code that they provided in the tutorials did not work, and I could not subscribe to an MQTT data feed or create the server. Is this chapter mandatory from this worksheet ? And also, do you know any other tutorials that could work regarding this issue ?
Gabriel Dumitru