@WilliamLai ...
Unfortunately, the Canvas Dashboard does not display a sub-dashboard layout as you've shown in one of your images. All your courses appear at the same "level" on the Dashboard. However, courses are usually separated out by term/semester...which you could see on your "Courses" >> "All Courses" screen.
Since you are a New Member here in the Community, you might not yet be able to suggest a new Feature Idea until you participate more. But, here are the Guides I usually point people to:
Also, you might want to take a look at this blog: Welcome New Members
Hope this will be of some help to you...even though it's not the answer you were probably looking for.