I'm really surprised that there isn't a step by step guide anywhere to read (with pictures too!).

The reason is one I cited at the top of this FAQ entry:

Troubleshooting ethernet connections is a tricky business for professionals, let alone newbies. If you're setting up ethernet for the first time just for the purpose of connecting to the Rio Car, my advice is to forget it and just use the USB port. You really should have a working LAN in place for other reasons (such as file and printer sharing or broadband internet access) before you even think about plugging in the car player.

One thing that FAQ entry doesn't show is a picture of the physical topology of some likely configurations. I could add that. Between that and the troubleshooting steps, there should be enough information to get you going, but the problem is, I can't create a complete and generalized "how to create an ethernet LAN" document... that's just out of my scope.

You have to understand that the car player is just another ethernet device, and if you don't have the prerequsite basic knowledge of how to get computers onto a LAN at all in the first place, I don't want to take on the responsibility of being the all-knowing source of basic LAN tutorials.