Google Analytics, Facebook pixel

A new client has SilverStripe for their website CMS. I want to add Google Analytics code and the Facebook pixel but I don’t see how to add that. I’m most familiar with Wordpress sites. I’ve searched the forum and other FAQs, but I can’t find an answer.

Create a file named Analytics.ss and FPixel.ss. Inside those files paste the codes. Now go in the directory of your theme and put these files into the “Includes” directory
Now go in your theme directory, and open the file Page.ss. Go in the tags and write:
<% include Analytics %>
<% include FPixel %>

Should be enough doing this one time only in Page.ss (this page is contained in everypage). After that just check after some hours if you are receiving traffic