On your dashboard, there will be a section underneath “your tasks” with a workout section on the workout that you should be completing for the day (if it’s a rest day, it will say it’s a rest day).
You can click on the workout, and if you haven’t completed some of the workout lessons yet, it will prompt you to either complete those first or continue with your workout. If you click on the workout portion, it will take you to begin your workout for the day.
You could also click on the workout section on your dashboard, which will also take you to your workout for the day.