My new Mac is not showing my Airport Extreme Base Station in the Airport Utility. How do I get it to show up?

What model of AirPort Extreme do you have?

What operating system is installed on the new Mac?

If you click on the WiFi menu at the top of the new Mac, is there a check mark next to the name of the wireless network that the AirPort Extreme is providing?

Is the AirPort Extreme displayed if you check with other Macs and/or AirPort Utility on the iPhone / iPad?

Have you performed any troubleshooting steps? If yes, what were they?