Are you working with Premiere Elements 14/14.1 Mac or Windows?
Have you just installed the program and have begun a new project? If so, please give more time for the Music to appear in the program even though you have installed the program successfully. There are cases where the appearance of Music and other are delayed. Give the process max 5 hours and let us know the outcome.
Please post any other details related to this Music appearance issue. Have the Graphics all appeared?