I created about 12 hours of recording in audacity. (I created an audio of my book.) There are 12 one-hour files. So I exported them each as mp3 files only to realize that I wanted them all to be ONE mp3 file. What should I do? Do I have to go back to the original audacity files and combine them all into one file before exporting or is there a way to combine the mp3 files? I see that software is promoted elsewhere on the web but I’m NOT a techie and I’m leery of that. Thank you. 
Never do production in MP3. MP3 is a delivery format and it creates sound damage every time you use it. Far better to go back to the Audacity Projects – which hopefully you saved and still open.
Audacity doesn’t have Append Import, it’s a popular feature request, so you can shift-select or control-select all the aup files and double click. They will all open in their own production windows. You can then copy and paste 2 and up (one at a time) into the back of 1.
That’s the Reader’s Digest® version (and only one way). If you need more detail, write back.
Koz
Thank you, Koz. I didn’t get an email so I didn’t see your response sooner. I will try it that way - and I’ll write if it doesn’t work.
Better solution: Import the first file into a new project then use the Shift-Click or Ctrl+Click to add the others. That way you get them all in just the one Audacity window and can then do the copy/paste thing within that single Audacity environment.
The problem with that is that if DrDebH only has MP3 files and not a lossless format such as WAV or FLAC, then that method will loose some sound quality as Audacity will need to decode the MP3 files and then re-encode to create the joined together file as an MP3.
The way that Koz suggested involves only encoding once (the final export).
Another alternative method is to use MP3DirectCut http://mpesch3.de1.cc/mp3dc.html
This program is able to join MP3 files without decoding them first and thus avoids the problem of encoding twice.