OK permalinks to topic sections came in Moodle 4.2. (By the way the School demo site is on 4.4 not 4.3.) I assume your site is on 3.11 (not 3.1)
In Moodle 3.11 you can add a Section links block and get the section links from it.
A new section page displays the contents of an individual course section. Section names in the course page link to section pages. Any manually added section links of the form course/view.php?id=xx#section-z will continue working, linking to course page anchors.