I recorded a discussion using an Azden electret condenser microphone and a inexpensive digital Radio Shack recorder. It came out a stereo
recording, which isn’t necessary as the mike was mono, and it’s just a voice recording which I intend to upload to YouTube. So, in order to
attenuate the volume, which nearly saturates the entire field on Audacity I would need to click on ‘Amplify’? I did that once, but was confused
as to the choice of various decibel levels, and a self-adjusting peak value. Can someone give me a tip?
I’m guessing that it also sounds quite distorted. Unfortunately that can’t be fixed 
Yes, that’s probably the easiest way.
Sure 
The Amplify effect automatically adjusts itself to provide the maximum amount of amplification possible while keeping the audio within the “valid” range below 0 dB.
Signals and waveforms are usually measured in “dB” where “0 dB” is the maximum “valid” amplitude.
When a waveform touches the top or bottom of the track (shown as +/- 1 on the track’s vertical scale), that is 0 dB.
That means that to be quieter, the dB measurement must be a negative number.
Half the track height is approximately -6 dB.
To make the selected audio have a peak level of -6 dB, enter “-6” (minus six) in the “New peak amplitude (dB)” box of the Amplify effect.
Does that help?
The fundamental problem with [u]clipping[/u] (distorted flat-topped waveforms) is that it’s impossible to know the “original” height or shape of the waveform.
(Audacity has a Clip Fix effect, and there are other clipping repair tools, but in my experience they might make the waveform look better, but they haven’t fixed the sound.)
attenuate the volume, which nearly saturates the entire field on Audacity
Nearly?? We can only go on what you tell us. If you select View > Show Clipping, does your timeline turn bright red? All of those red portions are likely permanently distorted. Crunchy and harsh? That’s overload.
The digital system assigns numbers to the sound that you record. If you make sound too loud, the system runs out of numbers and produces serious sound damage.
You can use any number of tools to reduce the volume of the show (Effect > Amplify > OK is one), but both the distortion and the show will change in step. “Clipping” is a name given to overload damage. The blue waves on the timeline seem to be clipped off top and bottom instead of following a gentle up and down motion. Those clipped portioned are discarded, permanently, unfortunately.
Have you ever used this combination of microphone and recorder before? Which recorder is it — exactly? High end recorder systems have a method of changing volume during a recording. New recordists are shocked to find that they need to keep one eye on the volume meters in the recorder during a session. That’s why early systems had two people. Movie recordings still do.
Koz