'Lessons' distinguishes between teaching and playing. After the teacher clicks the Start Lesson button, student accounts will enter Lesson Mode, which means they will not be able to access anything else but what the teacher is working on.
Located under each classroom's Courses tab, it is available only for Coding Adventure courses.
When you assign challenges, student accounts go into Playtime, which means they can only play challenges relevant to the lesson (limits which challenges they can complete).
As a result, students will be less distracted during class time, which can improve their focus and attention.
It keeps track of your progress in each class since it saves which lesson plans you already taught. Once you end a lesson, it will automatically be marked as complete and will take you straight to the next lesson so you never forget where you left off.