The ISO file that you will download is an archive containing an image of the original source DVD and is about 1Gb in size. This file can either be burned to another DVD or mounted to a virtual disk (on your hard drive) using virtual drive software. Your operating system will probably know what to do with the file once you have it downloaded, but if do you need additional software Daemon Tools Lite or Alcohol 120% should do the job.
Once you have the ISO file in place, the rest of the process should proceed much like any other software installation.
See the following link for instruction on doing this with Virtual Clone Drive:
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