Followed this guide: https://www.emqx.com/en/blog/how-to-use-mqtt-in-nodejs to build my first MQTT integrated Express JS server with simple connection and a single client publishing messages and subbing to a single topic.
Learnt to run the EMQX MQTT broker with Docker, creating a TCP MQTT Connection, Subbing to topics, Publishing messages, and Using MQTT in an Express JS framework.