Not sure there tends to be a first set of drivers you need to download related to the motherboard and the chipset. After you load that driver a bunch of device appear like USB ports and ethernet.
Normally this is just load the motherboard drivers that come with the board. Problem will be can you just load the win8 motherboard drivers on windows 10.
Now if you have loaded the chipset drivers and the ethernet port does not appear in the device manager I don't know what you do. You would likely have to find a driver maybe from intel for that motherboard chipset that has better support of win10 if it even exists.
You are messing with a motherboard that is almost a full ten years old, technology has changed a lot.