If you want to have a search form, and searching tool on you website, use:
<?php BI_SearchForm(); ?>
You can determine if you want to allow to search on pages and/or on news by clicking a proper checkbox on "modules" part of your pilot. You can have the ability to proceed to search in pages only or in news only, or in pages and in news. You can't have search form without the ability to search nowhere at all, so if you unchceck both options BP will act like you checked both. You are welcome ;)
If you want to block searching on your site - hide (comment) f.e. like this
<?php // BI_SearchForm(); ?>
All parameters you can determine at "Modules" section of your pilot.