MQTT example for TTN UNO sending sensor data?

Has anyone got any pointers for example code or tutorials to help me get a test up and running to send MQTT sensor data from the TTN UNO via TTN Gateway? Many thanks.

How do you mean MQTT example for the UNO? TTN can forward using MQTT but the UNO doesn’t play a part in that… does it? I mean I send my TTN-UNO sensor data to TTN then use MQTT to call it up using node-red on my PI(gateway)