Is the Audio Mixer Working?

Question

Is the Audio Mixer Working?
I am following step by step in Steve Grisetti’s book to learn how to use the Audio Mixer on the Action Bar, in the Tools section.
As I read the information, when playing a video project (with audio), opening the Audio Mixer should
(1) allow volume adjustment, and
(2) reveal operating audio-level meters (which are like VU meters in old analogue equipment).
HOWEVER, I find that opening the Tools function immediately STOPS the video from playing, of course then also stopping anything related to the Audio Mixer.
So, how does one open/activate the Audio Mixer (or anything under the Tools function) while the video (including audio) is playing?
Thank you,
Howard
P.S.  I'm editing this post to add the following:
In my continuing practice with this new-to-me program, I just discovered the "Adjustment" function of the upper menu bar.  Similar to the operation of the Tools function, as soon as I click on the function, my playing video/audio project STOPS.  I cannot edit the engage the volume adjustment while the project is running.
While it's generally unreasonable for such a beginner as myself to state that I know how this program is supposed to operate, I have read both in Steve's book and in this user forum that audio should be adjustable WHILE the project is running.

Answer 1

Yes, I located Adobe’s so-called "Help", but it seems to offer only thematic tutorials, not a traditional help function in the form of an Alphabetical Reference Index.
With the traditional Alphabetical Index, one need only provide a word or two -- such as "Snap To" or "Sharpen" -- and the Help function takes the user DIRECTLY to a definition or explanation of that particular function or concept, not unlike a very comprehensive Index at the back of a well-written manual.
I also own the FULL version of Photoshop CS5. The Help function has gradually moved to referencing Adobe’s Internet support, but there is still the traditional indexed "how to" and other help explanations, though they are more difficult to access than in the older versions of the program.
I am a new user who (1) is trying with considerable time and effort to learn PE-11 and (2) has purchased Steve’s book.  However, because I have not found an Index-type source of help associated with PE-11, I have come this User Form far more often than would be necessary if Adobe had spent the time and money to include an Alphabetical Reference Index as part of the program, and not merely some general "how to" categories on their website.
If blame is to apply, it is on Adobe.  I have no idea how any truly new user (defined as never before having used ANY video editing software) could get by without the two of you (Steve and Hunt) on this User Forum.  I assume you are both paid consultants or contractors for Adobe, and I hope they’re paying each of you a Caterpillar-Front-Loader full of cash for what you do.  But really, a lot of small items posted to this User Forum would be unnecessary if Adobe had incorporated with PE-11 the type of Alphabetical Reference Index suggested above.
My two cents.
Howard