Installing Oracle database 12.1 standalone is very similar with 11g, but this time we choose the Minimal edition as our platform. So there's a slightly different. We need to install not only Oracle required packages, but also the packages required by the Minimal edition.
X Window System is not a native group to Minimal edition, so we have to install X before installing Oracle in graphic mode.
In this series of tutorial, I try to categorize scattered steps of installation process into 5 major steps, you can click them for more details: