What version of Premiere Elements on what computer operating system?
The generalized ideas....
1. Right click Timeline file and select Delete Video.
2. Export the file if Premiere Elements 13/13.1, Publish+Share/Computer/Audio where you can save it as .wav, mp3, aac, aiff.
3. Depending on the circumstances, right click the file, select Unlink Audio and Video, and then copy the audio for use in another part of the project.
4. All sorts of variations.
Please consider and supply more details so that we can customize a reply.
Great news. Great job of follow through.