Add a page to the WP admin add_menu_page( $page_title, $menu_title, $capability, $menu_slug, $function, $icon_url, $position ); ?>

functions.php

add_action('admin_menu', 'ak_menu');

function ak_menu() {
	add_menu_page('Page Title', 'Menu Title', 'administrator', 'new-pg', 'ak_menu_content');
}
function ak__menu_content(){ ?>
	<div class="wrap">
		<h2>Page Title</h2>
			<p>content</p>
	</div>
	<?php
}