How to change a theme slideshow on Windows10 the Simplest Way.

Press WinKey+R, then put this in the run line and hit enter:
control /name Microsoft.Personalization /page pageWallpaper

It will launch the old control panel, which has support for setting different wallpapers on dual-head configurations.
There you have it.... Just like your old control panel just hidden.. lol..

Re-Designed by @BonkINC