The Sound Effects under the Audio Tab in the workspaces are available in tryout as well as purchased version.
How long ago did you install Premiere Elements 13? And, have you updated it from 13 to 13.1 yet? If not, please do that.
But, there is a problem with these Sound Effects in that there is often a marked delay between the end of a successful program install and when Sound Effects appear in the program files and within the project under the Audio Tab.
If you have just installed the program, please leave the project open, and wait and give those Sounds Effects time to show up. It is a strange situation. If that does not work, then close the program, shutdown the computer, and then restart the computer and Premiere Elements, and determine the outcome regarding project Sound Effects.
If the Music Scores and Sound Effects are not all in place within 24 hours, please let us know and then we can decide what next.