Usually, the boost directory contains three files. In install.php, you can create tables and other stuff you'll need for your application. uninstall.php takes care that you don't leave too much stuff in the phpWebSite installation after the user wants to get rid of it.

You can also create a update.php, it will be called as soon as the user copied a newer version of the module over an older one which has been installed already. As soon as the user decides to update the module, phpWebSite will call update.php.

Here you can set up all the stuff that makes phpWebSite great.

boost.php contains the current version of your module as well as its short and its long name. Be sure to use a mod_title, that's actually pronounceable. Not something like phpwsbb (you'll have a knot in your tongue after speaking it out repeatedly) but maybe something like clock, forums, users, etc. As general as possible but as specific as necessary.

You should also set up $mod_class_files, $mod_sessions and $init_object, so they would represent your modulename. Have a look in the clock-module for actual examples.

config.php actually isn't touched by phpWebSite. But there are a lot of people, like me, who like to put some runtime configuration in it. In addition to a nice database-driven user interface.

controlpanel.php lets you define the icon that will show up in the controlpanel as well as a description and a target-tab for it.

And the layout.php is very important, too. You allocate actual screen-estate for your modules in here.

Actually, the clock module doesn't use all of the phpWebSite config-files. Peek around in other modules and find out about categories.php, module_rights.txt and search.php.

This contains -- very hard to guess -- the language files. The file has to be called modulename.language.lng. modulename is your modulename, language the two-letter version of the target language. Popular examples include en for english as well as de for german. Including the english file makes sense, so others can easily translate your module.

Each language file starts with lang:|:modulename. The following lines all contain translations, the format is a:|:original:|:translated. Again: See the clock module for examples, it's really easy. But a lot of writing effort...