If the system is installed, don't bother. First, download a USB flash drive startup disk making software. I used a USB flash drive startup disk making tool in the computer shop. Super simple, just a few steps. Download and install this tool, click "Start the USB flash drive with one button", then download and decompress the system iso you want, copy the gho file to the gho directory of your USB flash drive (build it yourself), and name it dnd.gho. When starting the USB flash drive, click "Install gho with one button".