Audio adjustments in PE13—how to make?

I have Steve Grisetti's Muvipix.com Guide to Photoshop Elements & Premiere Elements 13. In trying to boost the treble in the audio track for certain clips, however, I find his instructions woefully inadequate.  Here's the situation:

1. I have a two-hour television music clip that I cut into four separate clips—a different artist in each clip.
2. The audio in the first clip is OK, no changes needed.
3. The audio in the remaining three clips needs high frequency boost, a different amount in each clip.
4. Although Grisetti spells out the function of the sliders in the treble/bass adjustment panel, he doesn't indicate how to tell the program which clip should be adjusted.
5. Where should the CTI be during this procedure?
6. Should a clip that needs a treble adjustment be "selected" or highlighted?  If so, does the program know just to modify the selected clip and not the entire four clips?
7. How do I know that the sound on a particular clip has been modified?  Is there a visual indicator somewhere?
8. Is there some button that needs to be pressed, or a pull-down menu item that needs to be selected, to effectuate the change, as opposed to saving the entire file?
9. What I am saying is that it is not at all clear to me how to boost the high frequencies selectively on the individual clips, since there apparently is no feedback mechanism for the user to indicate that a change has been made other than to try to hear a sound change.
10. Can Mr. Grisetti, or some other knowledgeable person, tell me step-by-step, how to boost the treble on, say, just clip three from the four-clip file, and how I might certify that this has been accomplished?  I would be much obliged.