KDE Plasma wallpaper doesn't work

I use Manjaro Linux (Arch) with KDE. I want run "Simple Plasma Wallpaper with QML extension" in kdevelop, but that doesn't work. In README is written: "cmake -DCMAKE_INSTALL_PREFIX = MYPREFIX .. (MYPREFIX is where you install your Plasma setup, replace it accordingly)" I try so much dirs (/ usr / lib (or lib64) / qt / qml for example) and the result is one: > "file:///usr/local/share/plasma/wallpapers/org.kde.plasma.simple/contents/ui/main.qml" "Error loading QML file.\n28: module \"org.kde.plasma.private.simple\" is not installed\n"