[Newbies] Squeak - Beginning Morphic

Hello. I am trying to learn Morphic. I wish to create some sort of canvas, drop it into a movable, sizable, scrollable window, programmatically add say, a CircleMorph to it, and allow the user to grab and move the circle with the mouse.

I am having trouble figuring out the proper sort of canvas class that would be best for adding/deleting/moving simple morphs around. Also, I am unsure how to get that canvas into a usable application sort of window. Finally, how would I allow the user to interact with the morphs on the canvas?

I have searched through wiki.squeak.org a bit, but I really can't figure out the proper class for the canvas and how to manipulate it.

Thanks!