Step 3: Finally Usage and Wallpaper Change
-Now click on a theme you want to use
Note: You need to apply theme different than "Windows 7 Aero" to be able to change the wallpaper. "Windows 7 Aero" is used to revert to original settings which don't allow wallpaper change.
Wait patiently and don't panic it needs time to change the theme. Time needed for this operation is different for different PC hardware (slower PC=Longer Wait)
-After your theme was changed:
Go to the Wallpaper menu (top bar, in the middle) and choose the one that you've put in your "Sample Pictures" folder. Hit apply which is under the wallpaper gallery (change should be instant).
Enjoy your Wallpaper! (suggested way of enjoying is doing a Kirby Dance!)