[totaltec]

In Reboot:
/reboot/custom/reboot_service_head.tpl

At the bottom of this file I added:

{include file="custom/facebook_tracker.tpl"}

Then I created the file:
/reboot/custom/facebook_tracker.tpl

With the content:

{literal}
<!-- Facebook Pixel Code -->
<script>
!function(f,b,e,v,n,t,s){if(f.fbq)return;n=f.fbq=function(){n.callMethod?
n.callMethod.apply(n,arguments):n.queue.push(arguments)};if(!f._fbq)f._fbq=n;
n.push=n;n.loaded=!0;n.version='2.0';n.queue=[];t=b.createElement(e);t.async=!0;
t.src=v;s=b.getElementsByTagName(e)[0];s.parentNode.insertBefore(t,s)}(window,
document,'script','//connect.facebook.net/en_US/fbevents.js');

fbq('init', 'REDACTED');
fbq('track', "PageView");
{/literal}

{if $main eq "cart"}
  fbq('track', 'InitiateCheckout');
{/if}

{literal}
</script>
<noscript><img height="1" width="1" style="display:none"
src="https://www.facebook.com/tr?id=REDACTED&ev=PageView&noscript=1"
/></noscript>
<!-- End Facebook Pixel Code -->
{/literal}

Of course be sure to enter your pixel code where I wrote "REDACTED" above.