Using Windows 10, Audacity 2.1.2, Plantronics Audio 648 stereo USB headset. I think I obtained the exe installer rather than the zip version. I’m recording a novel to be uploaded to PBS station WILL in Illinois for the Illinois Radio Readers’ program. I have stopped and started several times during this recording which must be between 57 & 58 minutes long to accommodate the program. In one segment I noted that I have dropped at least a page of text that I previously recorded and need to know how I can insert the missing portion without recording over a subsequent portion of the reading that I wish to preserve. Thank you.
Record the missing section onto a new track, then split the previous recording at the point where you wish to insert the new part (http://manual.audacityteam.org/man/edit_menu_clip_boundaries.html), then use the Time Shift tool to slide the pieces left/right as necessary to line everything up. To avoid clicks at the joins you could apply a short crossfade at the joins (see: http://manual.audacityteam.org/man/crossfade_tracks.html)
Edit > Clip Boundaries > Split.
I could not figure out where Split was hiding (or what it was called). You don’t need any of the other odd drag-selections, intervals, etc. Just point to the place you want to put the insert and Edit > Clip Boundaries > Split. A heavy line will appear and you can use the Time Shift Tool (two sideways black arrows) to push the right-hand segment out of the way. Click anywhere in the blue wave and push.
The rest is as above.