Go back to "Artist Administration"
click "Album Manager"
click "Edit/Add Songs"
click "Upload Song"
Click the Browse button to find your file
then Click the "Upload" button
Will take several minutes, so don't close the browser window...
When it's finished, it will take you to a new webpage and ask information about the song.
You will get a lot more listens for your song if you make a post in the "mp3 Mixing Clinic". There will be a lot of great guys and gals that can give you very informative feedback over there (it worked very well for me)!