Add Custom Pagination Without Plugins

global $wp_query;
$total = $wp_query->max_num_pages;
if ( $total > 1 )  {
     if ( !$current_page = get_query_var('paged') )
          $current_page = 1;
     $format = empty( get_option('permalink_structure') ) ? '&page=%#%' : 'page/%#%/';
     echo paginate_links(array(
          'base' => get_pagenum_link(1) . '%_%',
          'format' => $format,
          'current' => $current_page,
          'total' => $total,
          'mid_size' => 4,
          'type' => 'list'
     ));
}