You should have already followed the Adding custom help pages recipe, and the resulting plugin should be active in your development site. Alternatively, you can get the resulting code (Chapter 3/ch2-page-header-output/ch2-page-header-output-v8.php) from the downloaded code bundle. You should rename the file ch2-page-header-output-v8.php as ch2-page-header-output.php before starting this recipe.