After update everything is drop..

OK,

My modified files are:
directory: css/bbpress.css (bbpress that is file with style forum)
file: header.php
file: footer.php
file: function.php

Directory css/bbpress.css has to be not moving/deleting.

Header (belowe my add code):

<link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Dancing+Script" />

  <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>

  <style type="text/css">
  #idletimeout { font-weight:bold }
  </style>

  <?php
  $mystring = "$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
  $findme   = 'HELLO WORLD';
  $pos = strpos($mystring, $findme);
  if ($pos === false) { } // Note our use of ===.  Simply == would not work as expected
  else {
    $user = wp_get_current_user();
    $allowed_roles = array('subskrybent2', 'subskrybent3', 'administrator');
    if( array_intersect($allowed_roles, $user->roles ) ) { }
    else {
      wp_redirect( home_url() ); exit;
    }
  }

  if( is_user_logged_in() ) {
    print('
    <style>
    #countdown { font-style: normal; }
    </style>');
  }
  if ( is_page( 'login' ) ) {
    print('hello world');
  }?>

NEXT IN HEADER:
<div class="countdown"><?php if( is_user_logged_in() ) { echo "GREAT"; } ?></div>

NEXT AFTER HEADER:
<div id="idletimeout">
          <p>Hello user</p>
        </div>

ITS ORYGINAL Hueaman CODE:
<?php $_header_img_src = hu_get_img_src('header-image'); ?>
        <?php if ( ! $_header_img_src || empty( $_header_img_src ) ): //@fromfull to keep ?>

          <div class="group pad">
            <div style="float: left; display: block;">
              <?php echo hu_site_title(); ?>
            </div>
            <?php if ( hu_is_checked('site-description') ): ?>
              <div>
                <p style="line-height: 28px; font-family: Dancing Script;">Regon:</p>
              </div>

Footer (belowe my add code):

<section class="container" id="footer-widgets" style="background-color: #eaeaea;">

NEXT IN FOOTER:
<div id="credit" style="<?php echo ! hu_is_checked( 'credit' ) ? 'display:none' : ''; ?>"> <p><?php _e('Wszystkie prawa zastrzeżone.'); ?></p> </div><!--/#credit-->

Function (belowe my add ALL code):

<?php
//do not remove this

/*
 * Get the most recently replied-to topics, and their most recent reply
 */
  function custom_bbpress_recent_replies_by_topic($atts){
  $short_array = shortcode_atts(array('show' => 5, 'forum' => false, 'include_empty_topics' => false), $atts);
  extract($short_array);

  // default values
  $post_types = array('reply');
  $meta_key = '_bbp_last_reply_id';

  // allow for topics with no replies
  if ($include_empty_topics) {
    $meta_key = '_bbp_last_active_id';
    $post_types[] = 'topic';
  }

  // get the 5 topics with the most recent replie
  $args = array(
    'posts_per_page' => $show,
    'post_type' => array('topic'),
    'post_status' => array('publish'),
    'orderby' => 'meta_value_num',
    'order' => 'DESC',
    'meta_key' => $meta_key,
  );
  // allow for specific forum limit
  if ($forum){
    $args['post_parent'] = $forum;
  }

  $query = new WP_Query($args);
  $reply_ids = array();  

  // get the reply post->IDs for these most-recently-replied-to-topics
  while($query->have_posts()){
    $query->the_post();
    if ($reply_post_id = get_post_meta(get_the_ID(), $meta_key, true)){
      $reply_ids[] = $reply_post_id;
    }
  }

  // get the actual replies themselves
  $args = array(
    'posts_per_page' => $show,
    'post_type' => $post_types,
    'post__in' => $reply_ids,
    'orderby' => 'date',
    'order' => 'DESC'
  );

  $query = new WP_Query($args);
  ob_start();
    // loop through results and output our rows
    while($query->have_posts()){
      $query->the_post();

      // custom function for a single reply row
      custom_bbpress_recent_reply_row_template( $query->current_post + 1 );
    }
  $output = ob_get_clean();
  return $output;
}
add_shortcode('bbpress_recent_replies_by_topic', 'custom_bbpress_recent_replies_by_topic');
/*
 * Executed during our custom loop
 *  - this should be the only thing you need to edit
 */
function custom_bbpress_recent_reply_row_template( $row_number ){
  // get the reply title
  $title = get_the_title();

  // trim title to specific number of characters (55 characters)
  $title = substr( $title, 0, 55);

  // trim title to specific number of words (5 words)...
  $title = wp_trim_words( $title, 5, '...');

  // determine if odd of even row
  $row_class = ($row_number % 2) ? 'odd' : 'even';
  ?>
    <div class="bbpress-recent-reply-row <?php print $row_class; ?>">
      <div><a href="<?php bbp_reply_url( get_the_ID() ); ?>"><?php print $title; ?></a></div>
      <div><?php print human_time_diff( get_the_time('U'), current_time('timestamp') ) . ' temu'; ?></div>
    </div>
  <?php

  // Refs
  // http://codex.wordpress.org/Template_Tags#Post_tags
  // http://codex.wordpress.org/Function_Reference/get_avatar
  // http://codex.wordpress.org/Function_Reference/human_time_diff
  // (template tags for bbpress)
  // https://bbpress.trac.wordpress.org/browser/trunk/src/includes/users/template.php
  // https://bbpress.trac.wordpress.org/browser/trunk/src/includes/replies/template.php
}
// allow shortcodes to run in widgets
add_filter( 'widget_text', 'do_shortcode');
// don't auto-wrap shortcode that appears on a line of it's own
add_filter( 'widget_text', 'shortcode_unautop');

// Add logout popup
function popup_js() {
	 if ( is_page( 'login' ) ) {
	 	if ( !is_admin() ) {
	 		wp_register_script('popup_logout',get_template_directory_uri().'/js/popup_logout.js', false);
	 		wp_enqueue_script('popup_logout');
	 	}
	}
}
add_action( 'wp_enqueue_scripts', 'popup_js' );

// ShowPrivateFile
function ShowPrivateFile() {
	$user = wp_get_current_user();
	$output='';
	$allowed_roles = array('subskrybent2', 'subskrybent3', 'administrator');
	if( array_intersect($allowed_roles, $user->roles ) ) {
		$output = 'Pliki dostępne tylko po zalogowaniu:</br>'.'</br><a href="https:/XXXXXXXX.pl/wp-content/uploads/Document/abcd.docx">Protocol.docx</a></br>'.
	}
	return $output;
}
add_shortcode("pokaz_prywatne_pliki", "ShowPrivateFile");
ORYGINAL CODE FROM HUEMAN:
load_template( get_template_directory() . '/functions/init-core.php' );

/**
* The best and safest way to extend the Humean WordPress theme with your own custom code is to create a child theme.
* You can add temporary code snippets and hacks to the current functions.php file, but unlike with a child theme, they will be lost on upgrade.
*
* If you don't know what a child theme is, you really want to spend 5 minutes learning how to use child themes in WordPress, you won't regret it :) !
* https://codex.wordpress.org/Child_Themes
*
*/

So could u Tell me what I shoild do with it if I dont want to paste code always after update?

Nope. I used parent Hueaman file. Now I see child file but I dont know how use it. I paste part of my code to the child but what next? where move this child file (place where should be this childs file) and how import child to the parent (oryginal) File?

Where is child theme folder?

Page-templates?

yes.
I dowload from:
https://github.com/presscustomizr/hueman-child/archive/master.zip

After unzip I have this file: hueman-child-master.

In this directory I have the following files:
function.php
screenshot
style.css

so If I understood correctly we edit this file and where paste those files?

OK, one genereal question.
In first point: when I am in admin panel Do I upload master.zip from: https://github.com/presscustomizr/hueman-child/archive/master.zip
or another file?
Second. How activate it?

Note: since each theme identifies sidebars and menus using unique IDs you may need to reset your sidebars and menus.

Ok If I everything well done, now I haven’t see admin bar and pop-up. So how can I restart this sidebars?