How can I pair my categories with my pages AND subpages?

The frustrated website is graciamariastudio.com using the Suits theme.

Similar to wanting my main page title (i.e. Entertainment) to include the categories (all) of the subpages (i.e. Cooking con Gracia & Turning Tables) I would like for my subpages to be linked to their respective categories (i.e “Cooking con Gracia” & “Turning Tables”). I made a category for each page and each subpages– idk if that was the right thing to do. I also modified my menus to follow the same pattern/structure of my pages and categories.
What I can’t figure out is where to put the code, and what the code is that can assign categories to certain pages and subpages.
So things I need just to be clear bc I know I can ramble..
need categories to be separated into: home (all cat of all pages), each page (to have the categories of each subpage), and for each subpage to have its category only.

I have slowly managed to edit my site through php learning as I go so please be gentle with jargon. I saw somewhere about queries I tried figuring it out but no luck.. it puzzled ..