If I use instructions as per https://codex.www.ads-software.com/Child_Themes I can’t have a working child theme.
Site is https://campingmonterosa.altervista.org/

Can you help??

functions.php

[ Moderator note: code fixed. Please wrap code in the backtick character or use the code button. ]

<?php
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
}
?>'
------------------------------------------------------------------------
style.css
'/*
Theme Name:     Camp-Maine Child
Theme URI:      https://webdevelopment.tamstradingpost.com/themes/camp-maine/
Description:    Tema Child per il tema Camp-Maine
Author:         Qui il vostro nome
Author URI:     https://example.com/about/
Template:       camp-maine
Version:        0.1.0
*/
/* =Theme customization starts here
------------------------------------------------------- */

.widget-area {
	float: right;
	width: 26.0417%;
	border-color: #E5E6E9 #DFE0E4 #D0D1D5;
	border-image: none;
	border-radius: 3px;
	border-style: solid;
	border-width: 1px;
	background-color: #DDDDDD;
}

.site-content {
	float: left;
	width: 66.1042%;
	border-color: #E5E6E9 #DFE0E4 #D0D1D5;
	border-image: none;
	border-radius: 3px;
	border-style: solid;
	border-width: 1px;
	background-color: #DDDDDD;
}

.wc-shortcodes-button.wc-shortcodes-button-success:visited, .wc-shortcodes-button.wc-shortcodes-button-success {
	color: #FFF;
	background-color: #474C8A;
	border: 1px solid #4CAE4C;
}

.main-navigation li a:hover, .main-navigation li a:focus {
	color: #EDEDED;
	background-color: #E3582A;
	border-image: none;
	border-radius: 3px;
	border-style: solid;
}

.main-navigation li a {
	color: #C8D848;
	line-height: 3.69231;
	text-transform: uppercase;
	white-space: nowrap;
	font-weight: bold;
	font-size: 1rem;
}

Dear ,
I need plugins to achieve online registration locally on my wordpress site. Also, it will display the summary of all registed delegate. I.e total number of all registered delegate, Total male, total female, total children . Thanks while expecting your kind assistance.

Thanks