The simplest way is to go to Settings > Reading and choose “Your homepage displays” – “a static page.” That will give you a dropdown so you can choose the specific WP Page you want to display.
Other options include creating a child theme or a custom theme, or in functions.php using pre_get_posts() to modify the main query on the homepage to only pull the 1 specific Post or Page you want to display there (this may not work in all themes – it just depends on what theme you’re using).