Here boost will look for the graphics referred to in the file conf/controlpanel.php.

Here are all your class files - your actual phpWebSite code! I usually include the config-file in the constructor.

There's something special about the inc-directory. If it contains a file called runtime.php, that file will be called on every page of your site!

That way, you can easily show boxes outside of your module.

It is a good habit to maintain at least a changelog and a quick guide, what your module is about. And please include some kind of contact-information. Where should people go, if they need support? If they have ideas? If they want to give you loads of money?

index.php is the dispatcher for your module. Always make sure, that the core has been loaded in memory. Here's also the place to instantiate your classes and fill the boxes with actual content. The clock-module demonstrates a minimal way of filling your main-box with content.