How to show blocks only in certain pages

Hi all,
I'm thinking on how to show blocks only in certain pages.
I would like to know where to start from...

The basic idea could be to show the home page with a very basic navigation block, that takes users to show for example stories, weblinks etc.
When I choose stories, I would like to show a block for every vocabulary related to stories, and the same with weblinks, and so on......

Could you please suggest to me some code and where to put it ??

Thanks a lot

Matteo