On an iPhone 7 or iPhone 7 Plus: Press and hold both the Side and Volume Down buttons at the same time. Keep holding them until you see the recovery-mode screen. On an iPhone 6s and earlier, iPad with a Home button, or iPod touch: Press and hold both the Home and the Top (or ...
First, boot into Recovery or Internet Recovery Mode. You do this by restarting your Mac and holdingCommand-R(Recovery Mode) orOption-Command-R(Internet Recovery Mode) when the gray screen appears. Once you are safely within the confines of Recovery or Internet Recovery Mode, clickUtilities > T...