You should be more specific about what does not appear where. Eg, is the homepage containing a list of, say, the latest 10 articles, and it is not refreshed when a new article is published? Or is an article edited and its new version does not appear?
The best place to get you started with eZP wonderfully complex (and powerful) caching mechanisms is in the online docs: http://doc.ez.no/eZ-Publish/Technical-manual/4.x/Features/View-caching
Principal Consultant International Business
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Gaetano is pointing you to the right direction. eZ Publish has a default configuration that handles the most common content structure / caching interactions. When your structure doesn't match these, view caching configuration needs to be updated accordingly. It isn't very complex once you know how it works.