You wish to answer the available quizzes ("To Be Completed"), consult those to which you have already answered ("Completed") or those to which you have not replied and which are no longer available ("Missed")?
To do so, you just need to:
Click on "Quizzes" in the left menu. Then you access the quizzes "To Be Completed" and can answer them.
Click on the "To Be Completed" drop-down button to access the quizzes completed or missed.
By clicking on "Completed" you access the quizzes to which you have already answered. You can then consult your past scores, as well as the content of the previous quizzes: questions, proposed answers, answers you gave and explanations of the correct answers.
By clicking on "Missed", you access the quizzes to which you did not answer and which are no longer available. You can still consult these quizzes: questions, correct answers and explanations of the correct answers.