This guide is intended to help a developer get up and running using a Apple Mac. There is also an assumption that you are attempting to setup one of Apples recent operating systems (El Capitan, Sierra or High Sierra).
Whilst your device is off, insert the bootable USB with the operating system install. Press the power button and hold the alt
key to bring up the boot menu.
If you've held the alt
key correctly, you should be presented with a screen that looks like this.
You want to select something similar to install macOS
.