WisGate Developer CM4 - How to configure and connect to chirpstack

Hello
I´m new to the WisGate Developer Gateways and i´m looking for help or some documentation to configure them.
I´ve two WisGate Developer Gateways CM4 and want to use them as forwarder to a chirpstack LoRaWAN Server. Till now, i haven´t found any documentation on the RAK website how to log in an configure the developer Gates CM4.
I was able to connect my CM4 via a router and by putty SSH terminal, but the username and password (pi and raspberry) does not work in my case. Then i found another solution which allowed me to login with user rak and password changeme, but after that the command “sudo gateway-config” was not found.
Would be nice, if someone can help me.
Thanks in advance
Best Regards
Johannes

I also tried this installation Guide.

The Guide says, that there should be a SD Card included and you need the latest firmware flashed onto the SD. But in my case, there was no SD Card included and i don´t find any firmware to download or link to the firmware for the CM4.
Does anyone has already used the CM4 succesful? How was it configured?

Did you find solution. I have a similar issue