What do you have on Video 1 and Audio 1 of your project?
Do you want this song as a soundtrack or as a substitute for audio that is on Audio 1 from your video?
Assuming the the music file is saved to your computer hard drive...then you would use Premiere Elements 8.0/8.0.1 to Get Media/Files and Folders to import the song into the media and then you would drag the file to the Soundtrack or Audio 1 of the Timeline view.
As with all users with Premiere Elements 8, I always ask
a. Are you running the program from the Premiere Elements 8.0.1 Update
b. Do you have the automatic Background Rendering and AutoAnalyzer features turned off.
Please let us know if you have any further questions on your Premiere Elements projects.
Welcome to the forum.
Along with the answers to ATR's questions, I have one more:
What is the format of the music file, that you wish to add?
The reason that I ask that, is that sometimes, MP3's can have issues, but a PCM/WAV @ 48KHz 16-bit should Import (Get Media) perfectly.