I suggest that you start downloading the Getting Started KT2007 tutorial... 
Although this tut was created for the previous KT version, basics remain the same, only the GUI has changed, the engine has been optimized and many new features has been included...
The Material Editor has been completely re-designed - but again, the functions are similar and should be easily adaptable... 
The new Getting Started KT2008 Echo tutorial has been delayed a little, but will become available within the next 1-2 weeks... 
Download some - or all - of the free KT material libraries from our repository and apply some of these to your textures...
(Please note that there's a total of 19 material libraries currently available, and more to come very soon...
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And please note that it really isn't necessary to fiddle with all materials... Most of them can be used directly from SU... 
My best advice will be that you make a simple scene/model to begin with...
This could be a simple room with a window... Place a few objects (I.e. a chair, a table etc.) inside the room and start playing with KT... 
And if you have questions or want additional help, I recommend that you visit the KT Forum, where you'll find many helpful tips and tricks as well...
Looking forward to see some renders in near future..!! 