The easiest way to start working with VBA is to record a macro. This can be done in Word 2003 by accessing Main Menu -> Tools -> Macro and hitting the “Record new macro” button. In Word 2007, it is done by accessing the Developer tab in the main menu and hitting the “Record macro” button.
You will then be taken to a screen asking you to name the macro and decide where it should be sorted (template or current document). You can also assign a shortcut to your macro, so it will be executed each time by hitting certain key combination.