So back in early May 2015, (I know, like it was sooo long ago..) during the MS Ignite Conference, Microsoft released Technical Preview 2 for Server 2016.
The installation, regardless of what you select, only installs the CORE installation to reduce the OS footprint and minimize the security impact.
But what if you want the GUI? You can enable the GUI or (Server Graphics Shell) from within Server Manager. See, I already learned-ya something new today!
I will show you how below.