Click the Assessments menu in the Navbar and select Quizzes & Exams.
Click the Action Button next to the quiz.
Select Edit from the menu that appears.
The Edit Quiz page will appear. Click the Restrictions tab.
Scroll to the bottom of the page and click the Add Users to Special Access button.
If applicable, set an alternate Due Date.
Set the Start Date and End Date to create a window of time you would like to allow the student to access the quiz/exam.
Choose Enforced Time Limit to assign a longer window of time for a student or students.
Scroll down and click the checkbox(s) next to the student(s) these settings will apply to.
Click the Add Special Access button.