Plugging in an iPhone over USB and selecting iPod in the Media menu in the car will automatically sync up the phone's music library.
With USB not being possible, you need to connect over Bluetooth instead.
If you press the Media button on the Volvo V60 (2016), you can then select Bluetooth and start the pairing process.
On the LG G6, you need to go to the Bluetooth screen in the Settings menu. One nice thing about the LG G6 is that you can stay connected over Bluetooth to both your car and another Bluetooth device like your Bluetooth headset.
After you confirm that the Bluetooth pairing passkey on the phone matches that on the car, and accept the request for the car to access your messages, the pairing process will be complete.