If you wish to return to a course easily at a later date, whether you've started it or not, you can save it as a favorite for later reference. The Favorites page can be found in the menu under your name in the top right.
If you have not marked any favorites yet, you will not see any courses when going to your Favorites page.
To add a Favorite, when you are on a course page, click the outlined heart to make it a Favorite. Once marked as Favorite, the heart will turn solid blue.
Navigate to your Favorites page through the menu under your name in the top right. Click on any course on your list to continue learning.
To remove a course from your Favorites, go to the course page and click the solid heart (it will revert to outlined state). The course will no longer appear on your Favorites page.