Decided to give it a try and see if I could make my own desktop layout, but I found out there is no visual editor.
Creating a new scene can only be done by writing or downloading a script and altering or adding code.
Oh well, too bad, it doesn't look very difficult, but not easy enough for a quick try out.
Think I'll buy Wallpaper Engine on Steam: https://store.steampowered.com/app/431960/Wallpaper_Engine/
Only 4€, can use mp4 and do a lot more.
Looks like fun, always wanted to make a cool animated desktop wallpaper with video, but never thought of searching for a 3rdparty tool to do that.