First of all, you should create a template file for your one page. Let’s call it template-one-page.php. The template name, commented inside the file, is the name that will appear in Page Attributes -> Template when you creating a page inside admin panel. After that create a page, ie Home, and assign as template your template. If you want your page to appear as front page (when you enter mydomain.com this page will be shown) go to Setting->Reading->Front page displays->A static page and set as front page your page.

<?php 
// File Security Check
defined('ABSPATH') OR exit;
/*

Template Name: One Page

*/
?>

Normally a one page has sections. So we want to decide what type of sections we want. It could be pages, child pages, posts, custom fields (like a repeater from ACF) etc.

$id = get_the_ID(); // The page id

$sections = get_posts(array('post_type' => 'page', 'post_parent' => $id)); // get all child pages

foreach ($sections as $key => $section):

ID); ?>>
   echo get_the_title($section->ID);


endforeach;

Or with a Loop

$id = get_the_ID(); // The page id

$query = new WP_Query( array('post_type' => 'page', 'post_parent' => $id) ); // get all child pages

if($query->have_posts()):
    while ( $query->have_posts() ) : $query->the_post();

        
>
            

        
endwhile; wp_reset_postdata();
endif;