The good news is that you've already done the hard bit without even realising it

You have Audacity installed and you are able to record and play back - that's the hard bit.
Next we need to sort out a bit of terminology:
Audacity does not save audio files. Audacity saves "Audacity Projects".
An Audacity Project is not a normal audio file, it is a "project" and is made up of lots of little bits. The most obvious part of the Project is the "Project File". This is the .AUP file that is created when you "Save" the Project. The .AUP file is important because it tells Audacity what to do with all of the other parts of the project, but
it does not contain any audio.
When you make a recording, the audio data is initially stored in a temporary file, then if you save the project it is copied into a data folder. The name of the data folder will be the same as the name of the .AUP file, but with "_data" added to the end. For example, if you save a project and give it the name "hypno1", then a file called "hypno1.aup" and a folder called "hypno1_data" will ve created. The audio data will be in the _data folder and the .AUP file tells Audacity how to put all of the data back together to recreate the project.
To create a normal "audio" file, you need to "Export" from Audacity. Audacity can Export several different file types, but for best quality you should export as a WAV file. If the final format is going to be MP3, then it is best to leave encoding to MP3 to the very last step.
MP3 encoding reduces the sound quality. Editing an MP3 file and re-encoding it to MP3 will reduce the sound quality further. The effect is cumulative and cannot be fixed, so it's best to leave MP3 encoding 'till the very end so that encoding is only done once (by your sound guy).
Regarding your work-flow, it may be worth trying some different approaches:
Sinduction wrote:I would very much like to not have to record a 20 minute session when I can break it into 6 shorter files
Suggested work-flow 1
Start the recording and record a bit, then press the "P" key. Recording will be paused.
If you need to do a retake, just ignore the first take for now, press "P" to un-pause and record it again, then press "P" to pause.
When' you're ready to record the next bit, press "P" to un-pause, speak the next section then press "P" to pause.
When you have recorded all the parts, press "Stop".
Export the recording as a WAV file - this is your back-up file in case of emergency.
Now go through the recording and chop out all of the bad bits.
Export your finished masterpiece (preferably as a WAV file) and send it to your sound guy.
Optional step: If you may want to go back to the project at a later date and make any changes, "Save" the Audacity Project. I would advise creating a new folder for the project so that the .AUP file and the _data folder are kept safely together.
Suggested work-flow 2
Similar to work-flow 1, but use the "Stop" button or the Space-bar to stop between each section, then use
SHIFT+R to resume the recording.
Suggested work-flow 3
Make a recording of one section, then Export the recording as a WAV file.
Repeat for each section.
When you have all of the sections, create a new project and "Import" all of the audio files into the new project.
Each of the files will be imported on its own track.
Use the "time shift tool" (F5 key, or press the double headed arrow button <--> ) to slide each section left/right into the correct place.
Export the finished masterpiece.
WARNING for work-flow 3.
By default, when Importing WAV files, Audacity will "link" to the file rather than copying the file into the _data folder. This makes importing files a bit quicker, but it means that the Project will depend on the existence of those files. If you use this method I would HIGHLY RECOMMEND that you make the following change to the Audacity preferences:
Edit menu > Preferences > Import/Export
Set "when importing audio files: Make a copy ... (safer)"