Because you’re new to save a meltdown. Rather than editing functions.php (1 typo and your whole instance goes down). I suggest you either install one of the many code plugins that allow you to target a specific page. Or just add a code module to the content of the page and put your script in there.

Please use the code below. Add this code to your functions.php file:

    function cstm_script_spec_pg() {
        if ( is_page(123) || is_page('home') ) {
            wp_enqueue_script('custom-js', 'https://example.com/code.js', array(), null, true);
        }
    }
add_action('wp_enqueue_scripts', 'cstm_script_spec_pg');

Note:

is_page(123): Replace 123 with the ID of the page where you want to run this script.

is_page(‘home’): Replace home with the slug of the page where you want to run this script.