Begin writing your own short story.
Look back at the writng exercises you've done so far. Take your best idea, and go with it.
Don't ovethink this one. Nobody ever gets it exactly right the first time and there are plenty of revision techniques that will be covered in upcomming sections on the course materials. The important thing is to generate some raw material to work with later. Try to write at least the first three pages or 900 words
If you like what you've got, feel free to post it here. If you are struggling, feel free to share why.