Mqtt configuration with teltonika rutx50

I have difficulties in configuring MQTT on my rutx50 towards mosquitto on homeassistant. I installeren mqtt explorer and i do not see any message coming in.

Therefore I am looking on which pieces I exactly need to configure.

I have MQTT subscriber on the rutx50 connected to the mosquitto server. In the logs I see a Connect, but that is it. I have no clue where to look.

I assume i need to configure topics on the rutx50, but where?
Also I need to setup the broker to receive these packagemaker a i assume.
Another assumption is that I should be able to read the massages in MQTT explorer?

Am I fucked up by my assumptions or?..