Apple’s macOS Sierra launches on September 20th. Last year. John wrote a detailed article on how to do a clean install of OS X El Capitan. That is, if one were highly motivated to do an awful lot of work. The article applies equally to a clean install of macOS Sierra this year. If John couldn’t talk you out of it and a clean install is what you really want to do with Sierra, here’s a link to his 2015 tutorial so you can make a decision.
Check It Out: The Complete Guide to a Clean Install of macOS Sierra