Nav menu doesn't link to pages

Seems problem with permalinks as they work fine Id and you menus are set for postname. Did you check with your host if Mod_rewrite is enabled.

You may also check your custom menu settings.

I figured out what I did wrong, it was in the custom menu settings. But how do I change the path from https://thegritstree.org/?page_id=10 to https://thegritstree.org/home ?? I wanted to customize the links but I guess I’m not doing it right.

Try replacing –/?page_d=10 with just https://thegritstree.org. Anyway you have to change that otherwise, as it stands now, anyone typing your URL will be taken to an error page.