The thing that makes a Windows 8 clean install "clean" is the removal of the partition that the current operating system is installed on, as well as any auxiliary partitions that the operating system was using, usually for recovery purposes. This is what we're going to do over the next several steps.
Windows 8 Setup considers partition management an advanced task so before we can remove any partitions, you'll have to touch or click on Drive options (advanced).
Over the next few steps you'll remove the partition(s) for the operating system that you're replacing with Windows 8. Remember, it doesn't matter what operating system is currently on the computer - an old installation of Windows 8, Ubuntu Linux, Windows 7, Windows XP, etc.