Install the mod_subsection from https://github.com/aanabit/mod_subsection Make sure the current theme used is "classic" Create a course C1 and turn editing mode Add a subsection Subsection Sub1 in an existing section S1 Add an assignment A1 in the subsection Go to the course content/index Check the left navigation block: Ensure that you see the hierarchy: S1 When you click on S1 the menu updates (there should be a small reloading lapse) and you should see: S1  Sub1 A1 Finally you should see, by clicking on Sub1: S1  Sub1 A1 Ensure that you can fold/unfold the section and subsection Ensure that clicking on the subsection will redirect you to the subsection page Ensure that clicking on the Assignment link in the navigation block will redirect you to the assignment page