Let's create two sprites using the paint brush tool. One will be a Cannon, and the other will be Cannon Ball to be fired from the Cannon. Name and Size them to look similar to the challenge version.
Hover over the blue sprite button and select the Paintbrush option. Then on your canvas draw a Cannon. I recommend using the box and circle drawing tools.
Make sure to change Sprite 1 to Cannon, and Sprite 2 to Cannon Ball in the Sprite Menu. I like to use a size of 50 for both of my sprites but your numbers may be different. Always check that the Cannon Ball looks like it could be launched from the Cannon by mouse dragging it with your mouse over the Cannon.