What locations/instructions and which links are not working?
You may have a look at this thread: RAK831 with RPI 3B+ suddenly not working anymore
On RAK Wireless downloads you can find ready made images that can be written to SD card.
These images also have Loraserver installed which is not needed and not used when using the device as TTN gateway. There is a setup menu with an option to configure the device as TTN gateway (see included documentation for details).