There are 2 basic Lesson page types that the student will see: question pages and content pages. There are also several advanced navigational pages which can meet more specialized needs of the Teacher. The Lesson module was designed to be adaptive and to use a student's choices to create a self directed lesson.
The main difference between a Lesson and other activity modules available in Moodle comes from its adaptive ability. With this tool, each choice the students makes can show a different teacher response/comment and send the student to a different page in the lesson. Thus with planning, the Lesson module can customize the presentation of content and questions to each student with no further action required by the teacher.
Using Moodle Difference between Lesson and Book