Trying to move site to new domain – help please!

Trying to get domainA to show up on domainB without moving the files. I would like to keep the wordpress install on domainA. I thought I had it working correctly, but all it shows is the index.php file. None of the other pages will work correctly. Nothing else would work within the site. Here is my index.php file. Any thoughts anyone?

<?php
/**
* Front to the WordPress application. This file doesn’t do anything, but loads
* wp-blog-header.php which does and tells WordPress to load the theme.
*
* @package WordPress
*/

/**
* Tells WordPress to load the WordPress theme and output it.
*
* @var bool
*/
define(‘WP_USE_THEMES’, true);

/** Loads the WordPress Environment and Template */
require(‘https://domainB.com/&#8217;);
?>