The program in game Help pages include a web browser page to these web pages. A general overview of the game features is also included in the in game help. If you are in doubt about a menu item, then hovering your mouse over it will bring up a 'tool tip' which describes the menu function in more detail. If you are reading this from the in game help, then you are set. If you are reading this and not playing the game, then you will find that much more information is here than is possible to provide within the game itself, so you should continue here before playing the game.
To bring up the in game help, click on the 'Help' menu item in the main menu:
Tool tip example: