We will create search page for our custom component. First of all you will need to register a search page menu link for search sidebar. (Example Users, Groups, Your Name)

Please make sure you are using OSSN 7.2 at least

ossn_register_callback('ossn', 'init', function(){
			//register a menu item on search page load
			ossn_register_callback('page', 'load:search', function(){
					//keep other search arguments in place
					$args = OssnPagination::constructUrlArgs(array(
							'type'
					));
					$type = 'mycustom';
					ossn_register_menu_item('search', array(
								'name' => $type, //must be unique
								'text' => 'search:key', //this must be a langauge key not actual text as it handles itself ossn_print("search:key"),
								'href' => "search?type={$type}{$args}",
					));
			});											
});

Now we need to register page contents by using hook for search

ossn_register_callback('ossn', 'init', function(){
			//register a menu item on search page load
			ossn_register_callback('page', 'load:search', function(){
					//keep other search arguments in place
					$args = OssnPagination::constructUrlArgs(array(
							'type'
					));
					$type = 'mycustom';
					ossn_register_menu_item('search', array(
								'name' => $type, //must be unique
								'text' => 'search:key', //this must be a langauge key not actual text as it handles itself ossn_print("search:key"),
								'href' => "search?type={$type}{$args}",
					));
			});	
			
			//adding search page handler
			$type = "mycustom";
			ossn_add_hook('search', "type:{$type}", function($hook, $type, $return, $params){
					  	$query_string = $params['q'];
						//return your page contents here
						//example ossn_plugin_view('....
						return $query_string;
			});
});

Now adding a language file for search key. Create locale/ossn.en.php and add contents

<?php
ossn_register_languages('en', array(
			'search:key' => 'My Custom Component',									
)); 

Component can be found on https://github.com/opensource-socialnetwork/SearchHandler