[XeTeX] beginners trouble

[Martin Henning]

Hi,

i recently installed XeTeX with i-Installer to be able to use  
cyrillic within mostly german 8859-1-style documents. So i'm using  
utf-8 and just tried to XeLaTeX-typeset one of my 'old' documents.  
Should it work or is my understanding of the whole system wrong? I  
get many undefined control sequences etc. I've been looking for  
howtos or tutorials, but could really find any. The documentation  
includes some nice example of all kinds of fancy stuff, but  
unfortunately it's not a great help if you are new to the system. I  
understood X(La)eTeX as an addidtion to the TeX-system, meaning  
everything else continues to work, just some more unicode-related  
things will work additionally - wrong? :) Generally, cyrillic doesn't  
seem to be a problem font-wise, i just can't figure out how to  
quickly insert some russian within the normal document, which is  
supposed to be german. Some kind of example-file regarding this would  
be greatly apreciated!

Sorry for stupid questions, i have yet to understand what's going  
on... it seems to me.

Thanks,

Martin