How to Upgrade GNOME 3.12 to GNOME 3.14 in Ubuntu GNOME 14.10

This tutorial will describe you how to upgrade gnome 3.12 to gnome 3.14 in Ubuntu GNOME 3.14. by default Ubuntu GNOME 14.10 utopic unicorn shipped with GNOME 3.12, but, Ubuntu GNOME user can install the latest GNOME 3.14 from PPA.