In your directory /sites/all/, you have to create 2 sub-directories called “themes” and “modules” where your custom themes and modules are located.

What “hooks” in Drupal is all about? They allow your custom-built modules to interact with the Drupal core.  A hook is a function that is named foo_hookname(), where “foo” is the name of your custom-built module (whose filename is foo.module) and “hookname” is the name of the hook. Each hook has a defined set of parameters and a specified result type.

To extend Drupal system, your custom-built module needs to simply implement a hook. When Drupal wishes to allow intervention from modules, it determines which modules implement a hook and calls that hook in all enabled modules that implement it.

In Drupal 6.x there’re more than 70 hooks that you got to remember in case your internet is down. My next posts will show you how to implement each of these hooks in your custom modules.