I have been unsuccessful in trying to divide the CD into (using the player’s nomenclature) “tracks”, so that individual pieces can be accessed mmediately. I have added labels at the relevant points, but after export either as .mp3 or .wav there is no sign of the track number options when playing the CD in a CD player, or on the PC.
Please, what am I doing wrong, or failing to do ?? 
If you want split the CD into separate mp3 tracks, the thing to use is “export_multiple”
http://manual.audacityteam.org/o/man/export_multiple.html
which will create individual mp3 (or WAV) files according to the points you have labelled.
Many thanks for the advice. I’ll give it a try.
I could find no info about it in the program. 
The developers work hard to make the program’s functionality as “discoverable” as possible.
However Audacity is now a fairly complex and rich application - so it pays to read the Manual: Audacity Manual 
WC
CD players will not usually see track numbers and other metadata in the same way a computer will read it from the WAV or MP3. You will need CD-Text for CD metadata.
Gale