Hi @jtrocks . Is this what you're asking about?
How to use AirPort Express for AirPlay 2 with existing router
- Plug the AirPort Express into the wall and wait until it boots up.
- Go into your Wi-Fi settings on your iPhone, iPad, or Mac and join the new AirPort network.
- Click on the Other Options button.
- Select “Add to an existing network.”
- Choose your existing Wi-Fi network name from the list. Enter the password.