truing to find where to put code

it says to do this

Paste the //Commerce Code on your pages
This code should be inserted at the very end of your pages, just before the </body> tag.

The code needs to be present on every page where you’d like //Commerce to work. The best way to install this code everywhere is to add it to your site’s template.

The page I need help with: [log in to see the link]