Can't find search icon on navigation bar

Hi everyone,

I recently started using XWiki 13.3 since it is the default one when I build from the Debian repository in Ubuntu.

I need a site searching feature that should come with the installation as default. However, there is no search icon on the Navigation bar. I saw the search setting in Global Administration.
Screen Shot 2021-06-05 at 8.56.12 PM

I also manually typed the URL and went to the search page, but the page is empty. Screen Shot 2021-06-05 at 8.51.25 PM

I clicked edit page with “wiki” and here is the code of the search page:
Screen Shot 2021-06-05 at 8.55.16 PM

What should I do?