12" MacBook (early 2015) problems with ethernet adapters toUSB type c Iv'e got 2 Ethernet to USB type C adapters:
first one:
https://www.amazon.com/gp/product/B015CKP9NK/ref=oh_aui_detailpage_o00_s00?ie=UTF8&amp;psc=1
and second one i bought in a store, here is a picture:


the one I bought from amazon is not even detected in the network preferences but the usb ports does work, and the Ethernet works fine on my friend's windows computer with usb type c.
the second one works fine on my MacBook.

I want to return the second one to the store but i am not sure how to configure the working one to be configured on my El Capitan 10.11.6 (15G31) Mac.

What steps do I need to make ethernet work over USB C on Mac?
Here's how I troubleshoot a device over USB with the MacBook:


Open System Information
Select the USB section (it's in hardware)
Expand all the triangles to see all the connected devices.
Open Network system preferences (since you want to see an ethernet port appear)
Connect the device and watch for changes. After 60 seconds, refresh the System Information window if it doesn't self-refresh.




If you see the device connected in System Information but no network interface, you can try adding the interface explicitly. If that doesn't work, you would contact the vendor to see if/when their drivers are included with Apple's OS or if you need third party drivers. Or you could return the adapter and get a Belkin or kanex adapter, both of which work out of the box with all models of MacBook and Pro with USB C.

Also, consider upgrading to 10.12 if you don't have a good reason to not get the latest and greatest drivers direct from Apple.