From SME Server
When installing the netinstall ISO, you will be asked some basic questions (check the media, languages, keyboard layout etc.), followed by the question for the location of installation files. The options are CD/DVD, Hard drive, NFS or URL
When you select the URL option the required URL is provided as a mirrorlist.
Next step will be to select the packages to install, i.e. minimal environment to get a fully functional SME 10. Failure to do this step, will leave you with a CentOS 7 minimal.