Unable to find body tag in WP Bootstrap Starter Theme

I’m working with the WP Bootstrap Theme and I am trying to enable the tool-tip feature which requires popper.js.

I downloaded,installed and then tried to enqueue the popper.js script file in the functions.php file which did not work for me. Here is my code

function add_popper()
{
wp_enqueue_script(‘popper-js’, get_template_directory_uri . ‘/js/node_modules/popper.js/dist/popper.js’, array(), ‘1.14.3’, true);
}
add_action(‘wp_enqueue_scripts’, ‘add_popper’);

So, now I’m trying another approach which is to add this link “<script src=”https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js&#8221; integrity=”sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q” crossorigin=”anonymous”></script>” before the body tag.

But I’m unable to find the body tags in this WP Bootstrap Starter Theme.
Any help would be appreciated!
Thanks!