The only sections that are displayed are those that contain at least one published article (our emphasis) as well as the sections containing those sections. So you need to write at least one article and publish it. Of course, you may simply publish a dummy article to test the system.
I did all that and yet there’s still nothing displayed!
The public site uses a cache system, i.e. all the files are regenerated at regular intervals (every hour or every couple of hours, depending on the settings inside the PHP scripts). Such a system reduces the number of accesses to the MySQL data base and enables the site to be displayed in case of a MySQL failure — which happens more often than not with third-rate website hosts.
So you may need to force the page you think doesn’t work to be regenerated. To do that, first set a cookie in the private area, the effect of which will be to display a "Refresh this page" button on each page of the public site. Then click the button on the page you want regenerated — for example, on your index page if you want your new first sections to be displayed.