R8000 - bought a product using 2.4 ghz - our router is 5ghz - how can we have the router allow for

The R8000 has a 2.4ghz and 2x 5ghz radios. 

If you're using smart connect, you're probably only seeing one ssid but they're all there. They just use band steering to move devices between bands as needed. 

During setup of the fan, you need to have your phone connected to the 2.4ghz. Once its setup, the phone can be on any band.

Easiest way? Shut off smart connect and name the 5ghz radios something different (like add a 1 or 2 at the end of them). Then connect the phone to the 2.4ghz and setup the fan. Once its setup, you can turn back on the smart connect. Since the ssid is the same (smart connect uses the name that you set for the 2.4ghz), everything should still work and you only have one ssid.