Good morning, @AnnTran ...
When you are on your "Quizzes" index page that lists all quizzes in your course, do your quizzes have a white rocket ship icon? Or, do any of them have a black rocket ship icon? If they are white, those are all current Classic Quizzes. The black ones are New Quizzes. If you have any New Quizzes, you would either have to click on the name of that quiz and then click on the "Build" button...or from the "Quizzes" page, you can click on the three dots to the far right of your New Quizzes quiz item, and then select "Build". Any current Classic Quiz would not have the "Build" option.
Hope this helps a bit. Sing out if you have any other questions...thanks!