A stop lesson prevents a student from advancing further in the course until they fulfill a condition: submit an assignment, pass a test, or clear outstanding debts from previous lessons. This is useful when it's important to keep topics in order and prevent homework from slipping through the cracks.
To set up a stop lesson, open the lesson and click the gear icon — "Lesson Settings." You can only select one condition — you can't enable two rules in the same lesson.
Locking subsequent lessons is the most common option. The student sees and completes the current lesson as usual, but everything that follows will only open when one of the conditions below is met.
Complete this lesson. You can't proceed further until you complete the assignment or test for the current lesson.
Submit all previous lessons. Not only the current lesson is checked, but also the entire history: if there is unsubmitted work anywhere earlier, the program will not allow you to continue.
Turn in all important assignments. Only homework marked "important"—from this lesson and previous ones—will be counted. For instructions on marking this important assignment, see the "How to make homework mandatory for moving on?" card.
Close the lesson itself - this blocks not what comes next, but the current lesson itself: the student simply won't get to it until they complete the condition in the previous one.
Credit for the previous lesson. It's not enough to just submit something—you need to pass a test: a credit or a quiz.
Answering an assignment from the previous lesson. Simply submit your answer—as soon as it's submitted, the lesson opens.