I’ve seen this question before so here goes:
With Pinnacle open to Edit, click Album > Sound Effects. You will see about 20 different categories of sound effects.
Click the downarrow on the address bar. You will see options Sound Effects, More Sound Effects, and My Music. Select My Music and navigat to the mp3 files you want to add.
Select the song you are interested in, it will play for you. Drag it to the music channel of you choice in the edit area near the bottom.
Another way is to put a shortcut to your music in your sound effects at:
C:/Program Fils/Pinnacle/Studio 9/Sound Effects
The shortcut will point to your music.
Good Luck, Hurle