Boot your Mac ... El Capitan and earlier. When you're sure about your decision, click "Erase" and confirm. Finally, quit Disk Utility and select "Reinstall macOS" or "Install macOS" (or Mac OS X ...
In this article, we’ll explain what’s in the latest version of the Sequoia beta, what you need to do to get your hands on a copy, how to install it ... version of the Mac OS.