Boot from USB drive containing Mac OSX dmg file

Have you tried another USB port or use another USB thumb drive?

https://forum.amd-osx.com/viewtopic.php?t=3276

I tried another thumb drive.

You may have to bless the disk from a Mac system first.

 bless --folder "/Volumes/Mac OS X/System/Library/CoreServices" --bootinfo "/Volumes/Mac OS X/usr/standalone/ppc/bootx.bootinfo"

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man bless

BLESS(8)                  BSD System Manager's Manual                 BLESS(8)

NAME
     bless -- set volume bootability and startup disk options

SYNOPSIS
     bless --help

     bless --folder directory [--file file] [--bootinfo [file]] [--bootefi [file]] [--label name | --labelfile file] [--setBoot]
           [--openfolder directory] [--nextonly] [--shortform] [--legacy] [--legacydrivehint device] [--options string] [--personalize]
           [--quiet | --verbose]

     bless --mount directory [--file file] [--setBoot] [--nextonly] [--shortform] [--legacy] [--legacydrivehint device]
           [--options string] [--personalize] [--quiet | --verbose]

     bless --device device [--label name | --labelfile file] [--startupfile file] [--setBoot] [--nextonly] [--shortform] [--legacy]
           [--legacydrivehint device] [--options string] [--quiet | --verbose]

     bless --netboot --server url [--nextonly] [--options string] [--quiet | --verbose]

     bless --info [directory] [--getBoot] [--plist] [--quiet | --verbose] [--version]

     bless --unbless directory

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How do I get to a command prompt to execute?  is that under utilities because I don't see it.

You need to have access to a computer running OS X to run the above command.

So basically I can’t run the above command because the drive is new

Here's the thing:

Apple licenses OS X to only run on Apple computers.  If you did this from a Mac, all would work just fine.  You're trying to do it from Windows, something they don't officially support, so it's all a hack.  You'll need to get your hands on a Mac and see if it works, once it works, then you can attempt it on your non-supported platform.  Other people have done it, but they likely had access to mac hardware to get started.

A DMG file is also not an ISO.  It might contain an ISO and can be converted into an ISO format, but creating a bootable image from it can really only be done from a Mac, as officially supported by Apple.

Unless, you also match the hardware, there won't be drivers for your hardware, and it's going to run so excruciatingly slowly that it's not worth the time and effort, except as a proof of concept.  I've done those for some people just to prove that it can be done, and it either sat idly for the occasional showing off or it got wiped and replaced with Linux.  You'd save so much time just getting an older Mac.

But that’s the thing, I AM using this on a MacBook Pro.  I’m not sure I understand if you mean that I should run the boot disk on a working Mac first but I’m confident the file works fine.  The only thing is if I can just create everything from a Mac first then everything will probably work...