Creating my own theme

A link would be nice ?? If you use semantic markup etc, it wont take long to integrate your current design in WP

I’d suggest to find a theme that is close to your own layout and try to tweak that one – instead of going with the deafult, for example.
https://themes.wordpress.net/

As for designing a theme, start here: Blog_Design_and_Layout

The site is https://www.speedrecovery.com. So not sure if something like that would be easy to do in WP.

not sure if something like that would be easy to do in WP.

Actually, it has nothing to do with WP. It’s about your skills with HTML and CSS.
You can make a theme for WP as you want.

Should I create the theme using Dreamweaver? I have a template for the site in there. Ideally I would like to use the existing template and add tags in to provide the content from WP. If that isn’t too easy, I just want the easiest method!

If you have a “template” = a html/php file that looks exactly as you want, you just have to convert it into a WP theme.
Themes

Background: https://boren.nu/archives/2004/11/10/anatomy-of-a-wordpress-theme/
https://www.transycan.net/blogtest/2005/03/31/visual-anatomy-of-a-wp-15-theme/

and you can use DW only in code mode/view (whatever is called) not as a wysiwyg!