I will do that although it raises an other question: What is the difference between a Gateway and a PackeT Forwarder??
Host: embedded computer on which the packet forwarder is run.
Gateway: a device composed of at least one radio concentrator, a host, some network connection to the internet
So, if I get it right: The Gateway is the combination of the RPi and the Concentrator (in my case the RAK831).
It's all there in the documentation .. but there is so much of it
Also: There is no "Raspberry Pi + RAK831 installations manual"
Is the IMST ic880a "the same"/"compatible" with the RAK831 (I think I have seen a reference to the ic880a in the setup instructions from RAKWIRELESS in the document "Getting started with the RAK 831 Lora Gateway and RPi3.pdf")?
LoRaWAN seems getting more complicated by every question I have
@kersing & @jezd: keep us posted!!! You are ahead of my order delivery.