First download it here
I call it winmanx--you can rename it to anything you like. Once downloaded (in Linux--it's a tar.gz so you can't open it in Windows) decompress it. tar -zxvf winmanx.tar.gz You'll see two files--one called winmanx and one called README. Look at the README
cat README | less
It should answer most of your questions. At any rate, copy the script somewhere in each users' path. This will have to be done as root.
cp winmanx /usr/bin/winmanx
Make it executable
chmod 755 /usr/bin/winmanx
It's meant to be used from text mode--it won't work from graphical mode. Instructions on booting up in text mode can be found in the linux faq and are also covered in the README.
So, at a console, just type
You'll be given your choice of KDE or Gnome
Thanks for using my script and I hope you find it useful