In the CMS, we have a separate tab only for quizzes. In that tab, you can find all your existing quizzes and you can also add new ones.
For new ones, add a title, the quiz question, ONE correct answer, and some wrong ones to test your workers. Hit Publish and the quiz can be added to a course.
Also, make sure to add the quizzes for each language you would like to train your workers with.