The installation of X does not require any additional steps.. but during installation, did you remember to include the Xorg sets? xbase44.tgz, xetc44.tgz.. etc?
If you did install them, creating a new account and typing "xinit" or "startx" is usually enough.
If by "installing" you mean having Xorg start automatically each time you boot your system... I wouldn't recommend that personally, but it can be accomplished by adding xdm_flags="" into your /etc/rc.conf.local file.
Now at this stage I'll need a bit more info..