The FreeBSD Foundation has once again made it easy for us to setup FreeBSD. This tutorial shows you how to configure the various desktop environments, starting from X Window System, to the environment of your choice. Follow the link below for the entire instructions.

freebsdfoundationdesktoptutorial

Full tutorial: https://www.freebsdfoundation.org/freebsd/how-to-guides/installing-a-desktop-environment-on-freebsd/