Many users instinctively open Disk Utility, select "Restore," and drag the DMG into the source field.
To create a bootable macOS USB installer from a DMG file, you must first convert the DMG into a valid macOS installer app (found in your Applications folder) or use the function in Disk Utility for older versions of OS X . Option 1: Using the createinstallmedia Tool (Recommended) create mac os x bootable usb installer from dmg
Once your USB is created:
Always use createinstallmedia when possible. Only use dd if you have a legacy bootable DMG (e.g., OS X Lion recovery disk). Many users instinctively open Disk Utility