My articles are not visible on homepage

If you added your posts and categories, but they are not visible on homepage, it is possible that sections on homepage still have default categories that come with demo.

In order to change them, navigate to page editor and in Edit Section panel, tab Posts, add your desired categories (if the fields are left empty, section will display posts from all categories).

Note that Article Container element also has category filters that you need to adjust to show your posts and categories.