removing unwanted audio

I am very very new to video editing of any sort. I have just finished transferring a family video from my Video camera to the computer using dvgrab. The resultant files are ****.dv. When I load them into kdenlive the audio and video are all on the same track. If I want to cut out the superfluous background noise, talk etc, and replace it with music how do I get to the individual sound tracks. Sorry if that doesn't make the best sense.