PHP API documentation

Pardon me for sounding stupid, but where is the PHP API documentation? How do you set custom toolbars and where the filebrowser is?

I know how to create an instance. But what about the rest of the PHP configuration?

<?php include("ckeditor/ckeditor_php5.php"); ?>

<?php
     $CKEditor = new CKEditor();
      $CKEditor->editor("content", $content);
?>