Framework For CMS Website With Custom Theme

I’m trying to create a CMS with no blog (at least, not yet) where the home page is a custom theme with horizontal nav bars, and each page linked from the home page uses the same header and footer but completely different content areas. From the documentation, it does not appear I can use child themes for the linked pages, but I can’t figure out what structure to use for them. Each of the linked pages, as well as the home page, will have dynamically (user) created content on them. I have them all done in html and css.

How do I structure this website from a WordPress standpoint?