Publish specified ESP32's data on Theengs gateway

I’ve succesfully configured Theengs Gateway on my HA and, i.e., when I switch on an ESP32 BLE device I see on MQTT topic this informations:

{"name": "ESP32-BLE-Nr3", "id": "E8:31:CD:CB:63:3E", "rssi": -76}

Anyway I’d like to see many other informations like , i.e., the value on a specified pin.
I think is a matter of Arduino IDE script but don’t know where to start.
Any idea?
Thanks in advance.