Where to add Facebook purchase tracking code in themes.liquid?

[JessieB92]

Hi, I am working on adding the script to track my purchases through Facebook. However, I cannot find where to add my event code; it states I need to add it to my order confirmation page. I have already added it to my "Order Status page" in my settings in the additional scripts section, but it is not active. I assumed I needed to add it to my themes.liquid section to edit my code. Yet this is causing me issues because I have not found the correct section to add. The cart section is not working. Does anyone know what section to add this coding for it to work?

Thanks!