Editing Source Code On Bluehost

I’m using the Specular theme on Bluehost with wordpress. I can’t find an option to edit the source code anywhere.
In File Manager I checked in public_html and wp-content, but didn’t find it. (The Theme source code is there, but not the actual pages.)
Does anyone know how to find this? Thanks

Surely you want to login to the WP admin and make amends there rather than trying to modify the theme PHP?

The GUI options don’t cover everything I want to do. I was hoping there would be some sort of html/php document for each page to edit. For example there is a home page which I hoped would be a index.php or home.php type file. (Or set of files.) So I could freely change anything instead of being restricted to the GUI’s options.