<?php
function custom_setup_nav() {
      global $bp;

	  bp_core_new_nav_item( array(
            'name' => __( 'About', 'buddypress' ),
            'slug' => 'about',
            'position' => 30,
		    'show_for_displayed_user' => true,
            'screen_function' => 'about_page',
		    'css_id' => 'about'
      ) );

	  bp_core_new_nav_item( array(
            'name' => __( 'Challenges', 'buddypress' ),
            'slug' => 'challenges',
            'position' => 50,
            'screen_function' => 'challenges_page'
      ) );

	  bp_core_new_nav_item( array(
            'name' => __( 'Contests', 'buddypress' ),
            'slug' => 'contests',
            'position' => 60,
            'screen_function' => 'contests_page'
      ) );

	  bp_core_new_nav_item( array(
            'name' => __( 'Photos', 'buddypress' ),
            'slug' => 'photos',
            'position' => 70,
            'screen_function' => 'photos_page'
      ) );

	  bp_core_new_nav_item( array(
            'name' => __( 'Videos', 'buddypress' ),
            'slug' => 'videos',
            'position' => 80,
            'screen_function' => 'videos_page'
      ) );

      // Change the order of menu items
      $bp->bp_nav['friends']['position'] = 40;
	  $bp->bp_nav['groups']['position'] = 90;
	  $bp->bp_nav['forums']['position'] = 100;
	  $bp->bp_nav['messages']['position'] = 110;

	  // Remove a menu item
      $bp->bp_nav['notifications'] = false;
	  $bp->bp_nav['settings'] = false;

	  // Change name of menu item
      $bp->bp_nav['activity']['name'] = 'Home';
}

add_action( 'bp_setup_nav', 'custom_setup_nav' );

function about_page() {
   add_action( 'bp_template_title', 'about_page_show_screen_title' );
   add_action( 'bp_template_content', 'about_page_show_screen_content' );
   bp_core_load_template( apply_filters( 'bp_core_template_plugin', 'members/single/plugins' ) );
}

function about_page_show_screen_title() {
    echo 'About Page';
}

function about_page_show_screen_content() {
   echo 'the content of the page';
}
?>