What is FreeBSD?
FreeBSD is an advanced operating system distributed under the 2-clause BSD license. The FreeBSD website has all the information needed (especially the handbook) to install and configure FreeBSD itself.
The KDE/FreeBSD website is supposed to be the definitive source of information. Additional information for developers can be found on the FreeBSD KDE SC 4 wiki.
Building KDE SC trunk under FreeBSD
Please see the page on building KDE SC for general instructions. See the page on building KDE SC under FreeBSD for specific information for FreeBSD.