For install google manager in prestashop 1.7
Add link in templates/layout/layout-both-columns.tpl
<script async src="https://www.googletagmanager.com/gtag/js?id=ID"></script>
Step 2 add literal for accept by Ps
{literal}
<script type="text/javascript">
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date()); gtag('config', 'ID');
</script>
{/literal}
Add link in templates/layout/layout-both-columns.tpl
<script async src="https://www.googletagmanager.com/gtag/js?id=ID"></script>
Step 2 add literal for accept by Ps
{literal}
<script type="text/javascript">
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date()); gtag('config', 'ID');
</script>
{/literal}