I have been listening and reading about what a wonderful tool Audacity is for a long time. Now I finally took some time to download and test it. It worked.
I created a simple mp3 file with my gibberish and some background music. I tried to use a demo music file on my pc for background music but these files could not be read in Audacity. So I imported an mp3 from my husband's PC and ended up with another track next to the recording of my text. I then edited both tracks; deleted the silences, decreased the volume of the background music, moved my text a bit forward, so that the recording starts with some intro music first; and exported the file as my first mp3.
I followed these instructions to make the mp3 recording of my voice, and these for adding the background music.
Now I need to learn how to embed something like this in a blog.