Thank you so much! The slider works now, but one more issue:
I am on the main menu, and my music is playing. Normal. I click on the Options button and go to the options menu, but the music self-pauses. Strange. When I move the slider, the music resumes and the volume changes along with the slider and it becomes normal again. Even more strange.
I tried doing System > On start of layout > Audio > Resume, but that didn't work. Note that I was adding Audio > Resume to a System > On Start of Layout that I already had set up.
I can update the file and give another link. I am storing the file on my desktop and every time I save I just replace the old file.