You need to download the KTM MyRide app (£8/€9) to your smartphone. If you want to operate without a data service you can also download the country maps to your phone. The Bluetooth (optional) symbol on the combination instrument actually refers to a pairing of a device via KTM MY RIDE
The navigation app is fairly basic, and the display in the bike is just directions and pictograms. For short road trips it is fine. But not at the level of a real GPS or phone app like waze, google map or calimoto.
Note that early bikes had problems connecting to phones and showing navigation. See early faults, the bike may need a software update.
Very old bluetooth devices may have problem communicating with the bike. The first gen Sena SMH 5 and 10 for example, the ones without USB port for updating, will not work properly.