Heather.php file

I just installed X-Theme and is giving the following error:
Error : Please fix your theme to make plugins work correctly:
Go to the Theme Editor and insert <?php wp_head(); ?> just before the line of your theme’s header.php file.
I am new on this I I don’t find that line, this is what I see:

<?php // ============================================================================= // HEADER.PHP // ----------------------------------------------------------------------------- // The site header. // ============================================================================= ?> <?php x_get_view( 'header', 'base' ); ?>

Hello,

Thank you for writing in!

Because this requires a template change, I’d advise that you setup a child theme. This allows you to make code changes that won’t be overwritten when an X update is released. After your child theme is setup, please review how we recommend making template changes in

Customization Best Practices.

Once you have the child theme setup, kindly open the file _header.php from wp-content/themes/x/framework/views/global, make a copy of it and place it in wp-content/themes/x-child/framework/views/global then you can edit the copied file since it contains the header code.