AirPort Express has enough peculiarities and special features that it deserves its own section. (I can say, “and the AirPort Express also” only so many times, you know.)
In this section, you learn how to configure AirPort Express’s wireless disabled mode, its special client connection mode, its profile feature, and its music streaming with AirTunes. I also explain how to handle resetting an AirPort Express via its hardware reset button, how to disable Ethernet, and how to modify the status light display.
In all cases, I assume that you have connected via AirPort Admin Utility to your AirPort Express.
It’s an odd idea to purchase a Wi-Fi gateway and then turn wireless off. But you might do ...