How to add a ne physical device via network interfaces

I have a new Device which is connectsble via an USB-C cable. On my Linux pc i can Plug it in an see two new network interfaces. I need to set a static IP via netplan to one of them (172.30.0.1) an could get the webpage via wget 172.30.0.2:8080.

If I try to make something similar at HO it does not work. First of all, i was not able to set a static IP via HO i need to configure it via /etc/network/interfaces (which is not persistent over reboots). Secondly I do not get any connection to the device.

Please help me I have no idea what to try next.