I want to install the plugin on one of my blogs and create reviews in one category only. So people can only post rating on posts within that category.

There are about a dozen threads about this below you can read:

http://tangler.com/forum/wprs/topic/65332

Send me an e-mail if you need more help

Ye I looked at it and have no idea what to do with that code. Where does it exactly go and what to put in it? I have an idea for you. I am sure a lot of people would appreciate it if you made some camtasia videos showing how to do this stuff.

Every theme is unique, I can't make generic instructions that would work for anyone, that's why I offer one-on-one help by e-mail.