2 Questions

Hi. I just start using Lyx. I read the Introduction, Tutorial, User's Guide
and still can't find what I'm looking for:
A) Although I did add Greek, I can't write in that language.
B) How do I add a Document Class to the list..? I have lots of
Unavailiable..

My machine is Windows XP Proffesional 2002 with SP2 , LyX 1.3.7, MikTex,
Python and all that it needs..