If the Ethernet is not detected, it's most likely the USB-C connection to computer is not securely connected.
Please do the trouble shooting steps below:
1.) Connects the second USB-C cable to computer securely, as it is illustrated at the picture below:
2.) Look at the Ethernet port, the activity LED should be running.
3.) Once the Ethernet port is running, then plug in the other USB-C cable to computer.
Please find the FAQ https://hypershop.zendesk.com/hc/en-us/articles/360051155452-How-do-the-cables-work- about how these 2 x USB-C cable work.