Chapter exams start on Strict: after submitting, students see their score and which questions they missed, but not the right answers. You decide when the answers come out, one chapter at a time.
Open the chapter
On the class dashboard, choose By chapter, then the chapter.
Choose the Exams tab
The box at the top says what students see today and how many have taken the exam.
Choose Release answers
The confirm tells you how many students will be emailed. Only students who have already taken the exam get the email and a notification.
Students who have taken it can then open Review your answers on the exam: every question, what they answered, the right answer and why. Their score does not change. Anyone who takes the exam after you release the answers sees them as soon as they submit.
Taking them back
Hide answers in the same place closes the review again. Emails already sent stay sent.
Showing answers automatically
In Class settings, under Chapter exams, Exam answer support sets what students see the moment they submit, for every chapter: Strict (score only, until you release), Guided (the right answers) or Open (the right answers and why). It is separate from the quiz and exercise settings.
Each exam is one sitting unless you reopen it. If you reopen an exam after its answers are out, the retake is open-book. See Let a student retake a chapter exam.