Bow you are on the right track!
Sharing files over Ethernet is a wall-developed methjod.
Here is a good starter from Gizmo:
[ur=]https://gizmodo.com/5430678/how-to-make-your-pc-and-mac-share-stuff-like-best-friends]How To: Make Your PC and Mac Share Stuff Like Best Friends[/url]
quote...
Networking is stupid. You'd think it'd be real darn easy to share stuff between PCs and Macs, but it's not as nearly simple as it should be. So, here's how to make 'em talk and share stuff like best friends.
He is right, it harder than it outta be. But he does help.
Talk to Me, Girl
So, assuming that your PC and Mac are both sitting comfortably on your network, wirelessly or otherwise (if you haven't gotten that far, you need more help than I'll be providing right here), there are a couple of different ways for the various machines on your network to talk to each other and share files. Think of 'em sorta like languages.
You will have to read the whole article to catch what he is saying. There are different methods of sharing from Apple OS and the Windows OS.
Windows 7 is rather easy. Turn on file sharing and select a folder to share.
Linux is easy. Use Samba. With Samba you see anything visible on the network.
The big advantage of using Ethernet is that you do not have to buy anymore hardware if the PC or device has Ethernet. And most routers now tie the Ethernet and Wireless together in the same local block. Smartphones Tablets have wireless.
Read over that article and come back here if you need to.
The USB device sold on Amazon is for Widows only. You would have to find a App in the Apple store to make it work. There is, and what I found was very limited.
EDIT: Watt I may be wrong. I did not try this free Apple App:
USB Disk SE
https://itunes.apple.com/us/app/usb-disk-se/id370531520?mt=8