How to add some white space as head bar to a theme( hugo-clarity) which provide hooks?

Can some please show how to add some CSS/HTML to create top/head bar in the hugo-clarity theme where it provide hook.

"Clarity provides some hooks for adding code on a page.

If you need to add some code (CSS import, HTML meta or similar) to the head section on every page, add a partial to your project:"

layouts/partials/hooks/head-end.html

Now, I have created a file, head-end.html file inside the hooks folder, How exactly do I need to do next? Thank you in advance.