You indicate that you want to test booting from the .iso image. This is not possible because a virtual optical drive will not exist (yet) when the PC is booting. Emulating an optical drive on bare metal is only possible when the software that is booting (like Windows or Linux) explicitly supports this.
Instead, you can use a virtual machine to test the .iso image. One such virtual machine software is VirtualBox. It is free and open source.
After starting VirtualBox, create a new virtual machine (with or without virtual hard disk, as required). After creating the VM, you can open its properties and place the .iso image in its virtual optical drive. When you then power on the VM, it will boot like a normal PC.
Using a VM will allow you to test the boot process without having to restart your PC.