After you have added your questions, you might want to review the time limit.
Each candidate's time starts ticking individually when they begin their attempt. They can turn-in their test before the time otherwise the test is auto-submitted when time runs out.
To change the time of the test:
Go to Settings panel from the left sidebar.
Click the pencil icon beside the Time Limit field and type in the new time limit in minutes.
That's it! The change is auto-saved and applied to any new candidates.