Create a search engine

something along these lines

function SearchFilter($query) {
  if ($query->is_search) {
    // Insert the specific post type you want to search
    $query->set('post_type', 'page');
  }
  return $query;
}

// This filter will jump into the loop and arrange our results before they're returned
add_filter('pre_get_posts','SearchFilter');

in your functions.php

perhaps

Looks like this plugin can be configured to search only what you want:

http://ww.wp.xz.cn/plugins/search-everything/

it says you can exclude posts but I haven’t used it.

try googling “wordpress search plugin exclude posts” or “wordpress search plugin only pages” or whatever

e.g. http://ww.wp.xz.cn/plugins/simply-exclude/

you mean you want to add the search box?

the code for that is <?php get_search_form(); ?> afaik

you might want to look in the widgets section, there may be a search box in there you can just drag into the sidebar.