Why is my quiz that was imported from another course not available to students?
You need to edit the dates of the quizzes. Click on "Quizzes" in the "Activity" block on the left of your screen:
Notice the wrong dates on all of the quizzes. Click on one of your quizzes.
Click on "Edit settings" in the "Settings" block.
Adjust your dates by looking in the "Timing" block and add a check beside "Enable" on the "Open the quiz" date. Verify the correct open date, then change the close date. you can also enable the "Time-limit".
Scroll all of the way down the screen and save.