How to configure clean installs of......

My goal is to wait until El Capitan arrives before attempting the installation of new Parallels desktop version and then, Windows 10. Want to start preparing, and will not attempt until a few updates for El Capitan have been posted.
My question is, what would be the most efficient methodology to install, reinstall if I wanted to do a clean install? I have of course back ups available on my time machine. Little confusing as I am not sure of the best way to clean install my mac startup volume and the next steps involving installation of Parallels and ultimately restoring files from time machine to the new Window 10..
Any guidance / suggestions would be appreciated.