Having a table full of rows in the MSI gets us halfway. The other half is defining a custom action that reads from that table and does something useful with the data at install time. The extensions that come with WiX already do all sorts of handy things, such as create SQL databases and tables, edit XML files, add users and set permissions, add websites to IIS, and so on. Your extension will add to this list, allowing an installer to do new, uncharted things! However, in this example we'll keep it simple and only display a message box for each row in the SuperElementTable table.
This is going to be a three-step process. First, we'll define the custom action in C#. Then, we'll embed the custom action DLL inside a WiX library (.wixlib). Finally, we'll embed that library inside our extension. In the same Visual Studio solution where we defined our extension, add a new project using the C# Custom Action Project template. Call it SuperElementActions...