That's a simple process of either right clicking on the desktop for the display properties there(much faster) or going into the Control Panel to change the display settings there with setting the background, going into the Appearances tab and advanced button there for desktop color, 3D objects, and other things from a dropdown menu.
Once you have the appearance, 3D objects, and the rest where you want them go into "themes" and click the save theme button to enter a name like "default" and click the save button. You then can log off without a full restart and see if the "saving desktop settings" message appears.