Question about iROX DWH-8

The whole set (display, 3 sensors and gateway) does not seem to fit together at all. I have neither managed to display the values of the 3 sensors on the main display nor to connect them to the gateway or the app (the manuals that can be found on the net do not match the hardware, etc.). More than slightly frustrated, I had put the 5 devices in a corner and now use the display and sensors separately, which is not the idea.

I am taking this request as an opportunity to ask Digitec for support. In this sense, thank you @Zwerg1981 for asking the question.