.../2/4/8GB version), just download the image file and write to the micro SD card with dd or other applications. Then plug in the micro SD card to your Raspberry Pi4. You can use iOS app and Android app named "VitOS Manager" to manage the VitOS.
VitOS V1.0 supports USB DAC as audio output device. You can connect your USB DAC to the USB port on your RPi4 board. With VitOS Manager, you are able to install Roon Bridge to the VitOS. Then you can discover the RPi4 board with Roon apps and play music.