To convert the html site to an exact duplicate in WordPress you will need to create either a child theme or a new theme from scratch.

You don’t really need to know PHP to build a theme. I used a blank Bootstrap theme as a base for my first theme because I wanted it to use Bootstrap’s responsive framework and default classes.

A good place to start is a blank theme like Bones or Underscores. They contain all the necessary PHP and template files. You just add your HTML and CSS.

some of my bookmarks:
https://premium.wpmudev.org/blog/convert-html5-template-wordpress-theme/
https://www.charityandbiscuits.com/blog/tutorial-convert-bootstrap-site-template-wordpress/
https://line25.com/tutorials/how-to-create-your-own-custom-wordpress-theme
https://blog.spoongraphics.co.uk/tutorials/how-to-build-a-custom-wordpress-theme-from-scratch

I now use my theme for every project and customize it accordingly.

If you have any more questions post em here: https://www.ads-software.com/support/forum/wp-advanced/