How to insert Google Tag into head of every pages

[Galaad]

Hello!

Google Tag Manager offers two tags to place into every pages of web sites

One in the head tag and the other in the body.

I tried to modify the TPL files to do so by adding manually at the end of  

- templates/_partials/head.tpl

- templates/page.tpl

I faced some issues with head.tpl.

It tried several positions into those files (top, bottom, in the middle, etc.)

Being careful not to break SMARTY templating.

The website broke everytime I tried to modifiy head.tpl

I then tried to insert the javascript part of the Google Tag Manager script tag to put it at the end of javascript.tpl

Surprisingly this broke the website either.

Do you guys have any clue how to do that properly?

 

Thanks a lot!

 

Galaad