Here is the plan.
Import your .mp3 into Premiere Elements 12 Windows, using Add Media/Files and Folders/Project Assets.
Do not drag the audio to the Expert workspace Timeline. Instead double click the .mp3 file in Project Assets to open the Preview Window.
In the Preview Window, use its Set In and Set Out points to trim the .mp3
a. if you drag from the Preview Window into Project Assets, you can generate these trims as subclips which can be used as project media
b. if you drag from teh Preview Window into the Timeline, you have media on the Timeline for export.
I have described this approach in a blog post directed more for video but which is applicable to audio.
a. You can selectively export segments of the Expert workspace Timeline by setting the gray tabs of the WorkArea bar to span the segment to be exported AND having a check mark next to Share WorkArea Bar Only in the Audio export settings area. The 2 are required for this to work for selectively exporting that audio.
b. Project Assets can be set up folders
Please review. More details if you are interested in exploring these ideas further.
Thank you for this very useful information. This is a huge load off my mind. I don't know how you figured out all these tactics and techniques, but thank you.
Glad that the information will help.
Please update us on your progress when you get the time.