With each command, it's assumed the installer is located in your 'Applications' folder and 'MyVolume' is the name of the USB flash drive. The command differs, depending on the macOS version you're going to install. In the next step, you'll enter a command in Terminal. Choose 'Finder' then select 'Go' from the menu bar. Connect the USB flash drive to the computer you wish to install macOS.
Once you have your bootable installer ready, it's time to move to the next step.