session types (9.1)
 

What do the other session types do? Why would I use them? Are they completely installed already?

blackbox
fvwm
icewm
mwm
openbox
twm
windowmaker
xfce
admin
failsafe

Most are other light weight Desktop environments or Windows managers. They are less resource intensive then KDE or Gnome. A lot are highly customizable although the defaults will look very bare if you are used to KDE. If they are on that lists, they should be completely installed and ready to use.

I tried the windowmaker... all I could do was start a console session.