There are 2 ways to get to the quiz:
1. From the blue course access page, which can be found via My Active Courses [1] then click on course title
2. Click on "My Account" then click "My Quizzes". You will find a list of all the quizzes for the courses you've purchased here. To start taking the quiz for a specific course, click on the name of that course.
Links:
[1] https://www.elotus.org/../user