Upload Multiple Files With media_handle_upload

here
if you use custom template past this in the begining

<?php
 if( 'POST' == $_SERVER['REQUEST_METHOD']  ) {
if ( $_FILES ) { 
    $files = $_FILES["my_file_upload"];  
    foreach ($files['name'] as $key => $value) {            
            if ($files['name'][$key]) { 
                $file = array( 
                    'name' => $files['name'][$key],
                    'type' => $files['type'][$key], 
                    'tmp_name' => $files['tmp_name'][$key], 
                    'error' => $files['error'][$key],
                    'size' => $files['size'][$key]
                ); 
                $_FILES = array ("my_file_upload" => $file); 
                foreach ($_FILES as $file => $array) {              
                    $newupload = my_handle_attachment($file,$pid); 
                }
            } 
        } 
    }

}
?>

in function.php

function my_handle_attachment($file_handler,$post_id,$set_thu=false) {
  // check to make sure its a successful upload
  if ($_FILES[$file_handler]['error'] !== UPLOAD_ERR_OK) __return_false();

  require_once(ABSPATH . "wp-admin" . '/includes/image.php');
  require_once(ABSPATH . "wp-admin" . '/includes/file.php');
  require_once(ABSPATH . "wp-admin" . '/includes/media.php');

  $attach_id = media_handle_upload( $file_handler, $post_id );
  if ( is_numeric( $attach_id ) ) {
    update_post_meta( $post_id, '_my_file_upload', $attach_id );
  }
  return $attach_id;
}

soure http://www.kvcodes.com/2013/12/create-front-end-multiple-file-upload-wordpress/