Update: Please cross-refer this reply with other replies below. Something in this thread is out of date.
Similar to Cubase, Dorico utilizes Windows Installer to install. You may want to check all available files with “.msi” extension on your DVD. Some of them installs Dorico, while some of them install the HALion sounds necessary for Dorico default playback.
NOTE 1: eLicense driver and control center installer is not in .msi format but in .exe format. If you install Dorico through .msi files, I suggest you to get the latest installer of eLicense Control Center from Steinberg website.
NOTE 2: If you have internet available, Steinberg Download Assistant should provide least hassles to you for the installation of Dorico main app. You may still want to install the sound libraries from DVD since these contents were not changed for years till now, saving your data fees from your ISP.