changing amplitude for selection within a track

Good day. I don't do much AV editing (I'm a still image guy), but I'm wearing a different hat this week for our small organization. I'm combining music with narration for an illustrated oral history project. I've been doing the audio work in Audition, and I'm working with CS6 since we already own a license for this. With both tracks loaded into a multitrack session, I can't figure out how to selectively adjust volume for the music around the ebb and flow of the narration (I could switch to the waveform editor, but timing this against the narration would be clunky at best and of course destructive). Though I've done multiple web searches and can see how to adjust volume for a track over an entire clip or fade in/out at the beginning and end of the clip, nothing I've found indicates a way of doing this selectively, within a clip and within a track. Can anyone turn the lights on for me here? I'm grateful for help with this.