Hello! My name is Cristiano. I'm an Independent Advisor. I'm glad to help you.
By default, the Desktop is located at "C:\Users[Your Username]\Desktop" on your computer's hard drive. However, it sounds like you have moved your desktop folder somewhere else, since you're not seeing any files when you look in the usual places.
To find out where your desktop is located, you can right-click on the desktop itself (i.e. the blank space on your screen) and selecting "Personalize" from the context menu that appears. From there, click on the "Themes" tab, and then click on "Desktop icon settings." In the window that appears, you should see a "Location" field that tells you where your desktop folder is located.
As for getting rid of clutter on your desktop, it's really just a matter of deleting files or moving them to another location. If you don't want to see the "Pictures," "Videos," and "Music" folders on your desktop, you can try hiding them by right-clicking on the desktop, selecting "View," and then unchecking the boxes next to those folders. If you've already moved the default locations of those folders to somewhere else, then you shouldn't see them on your desktop anymore anyway.
Hope that helps!