How can I display & split the audio & video from the same digitized clip?

Question

I digitized a scene into iMovie that I edited on a professional system which I don't have access to anymore. The whole scene is 1 clip. Now I see a few tweaks that I want to make, so I was hoping to do them in iMovie.
I want to "pull up" the audio in one section - meaning I want to take cut about 20 frames of audio from the end of a shot, and then move all the other audio up to fill the hole. To compensate for the missing 20 frames, I'll cut video off the head of the next shot. Some call this prelapping. Some call it an L-cut. Some call it asymmetrical trimming. Either way, I can't figure out how to do it in iMovie.
My clip appears in the timeline as one track - a single track that contains the video and 2 audio tracks. How can I display the audio that's tied to the video on its own track? Then I think I could split audio & video wherever I wanted and trim things up - but I can't figure out how to do it.
Am I asking too much of this software?
BTW, I never see the option to "Split audio clip at playhead". I'm not displaying clip volume or waveforms. Choosing to display waveforms doesn't show me anything. Maybe iMovie thinks I'd only want to see waveforms of audio that isn't tied to my video-and-audio clips?
Thanks in advance for any help...

Answer 1

Jordon,
"Am I asking too much of this software?"
No, you're not.
You first want to select your clip(s) and choose Advanced>Extract Audio.
This will copy the audio from the video clip and place it on one of the two separate audio tracks while lowering the audio level to zero in the original video track.
You can now edit and move the audio independently of the video.
With the audio clip selected, you'll find you now have access to Edit>Split Selected Audio Clip at Playhead.
Matt