Modifying header.php file with body code for Google Tag Manager

Hey JonathanUstin,
If you want to edit the header.php file look for this on line 81 </head> and add your script before or after it depending on if you want the code to fire in the “head” or the “body”
Or you can add this code to the end of your functions.php file in Appearance > Editor if you want it in the header:

 function add_custom_gtm(){
	?>
	<noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-MN3P7B"
	height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
	<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
	new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
	j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:";j.async=true;j.src=
	'//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
	})(window,document,'script','dataLayer','GTM-MN3P7B');</script>
	<?php
	}
	add_action('wp_head', 'add_custom_gtm');

Please adjust the code to suit.
If you want the code in the “body” add this code to the end of your functions.php file:

add_action( 'ava_after_main_container', 'ava_after_main_container_mod', 10);
function ava_after_main_container_mod() {
	?><noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-MN3P7B"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:";j.async=true;j.src=
'//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-MN3P7B');</script><?php
}

Please adjust the code to suit.

Best regards,
Mike