Please be aware that this capability is only available on Android devices. Subscribers will not see this option if you have an iOS/Apple device.
If your Wave account already has a Beacon on account, you will see it as you sign it. Just swipe left to see where you can add your Android phone as a Beacon:
Select the option to turn your Android phone into a Beacon:
Next you have the option to name your "Android Beacon"
Afterwards, you will have the option to configure your Android Beacon with Shuffle if you have the subscritpion to Shuffle or a secure site.