There are 3 types of courses. Each course is associated to a pictogram, which gives you specific information about the kind of learning material is presented on the sequence. Here is a list of courses you can find:
Multimedia lesson : It has one or many medias just like videos, audio files or images. It can also have questions; so it can be evaluated.
Quiz : It is usually a course with different questions to evaluate the learner's knowledge.
Lesson : It is usually a theory lesson with text and possibly some explanatory images.