Google Tag Manager

You can use the following script in order to integrate Google Tag Manager into a site: https://gist.github.com/bigdigital/c7fe0256a4a066a6c9bc69b0a0330dfa ,
where ‘GTM-XXXX’ is Google ID.
Or use Dt Res Inc Master plugin
Install it, activate, then follow to Tools -> Dt Res Inc Master and place script to header and after body fields

fiig.1 “DT Res Inc Master” plugin interface