Premiere Elements 13 on what computer operating system? Have you updated 13 to 13.1 yet using an opened project's Help Menu/Updates.
To your immediate question....how do you want to edit the Movie Menus for Premiere Elements 13/13.1? There are many ways to customize the Movie Menu themes in the Movie Menu customization within the opened project.
However, there are certain changes in the themes that can be made only by editing the layers in the Layers Palette of the menu's .psd files on the hard drive. You can use Photoshop CS or higher for the latter. To get some ideas for this, please see the blog posts listed at the bottom of the following
Please review, consider, and supply more details.
Any questions or need clarification on the above, please do not hesitate to ask.