On the Course Home page, you have an Updates box on the lower left. If there are quizzes available, you will see a (number) Quiz available link. Clicking this link will take you to Quizzing Home. On this page you will see linked quiz titles followed by when it is available.
Also you can click the Quizzes tab upper left scarlet navigation bar. This takes you to the Quizzes home page. Any available quizzes will be hyperlinked.