Just as the photo illustrates above.
Basically create a new bus and adjust the fader for the volume level in which you would like to hear your audio files
Next, go to the Media tab and click the downward arrow and select "
Audio Preview Bus". Next, when the right arrow expands, you will see a list of buses and audio outs. Select the bus in which you created as the preview bus (
What ever you named the new bus), and you should hear the sample played, if not, restart Sonar and it should be available now.
I hope this helps,