If you google 'google analytics' you will find an online training course that is free. It explains all of these terms in detail and makes it fairly easy to understand. It explains why this information is important and how we can use the data.

What's the difference between Visitors: total visitors to a site Unique page views: Total separate visitors visitors to a page clicks: Number of clicks on a page total visits: Number visits to a page total (includes all visits even from the same persons) page views: (includes page views by the same persons on the same visit)