Write about three brief sentences describing what your story is about
Where is your story set? In the country or town? In a cafe? it is best to think of locations you know so you can easily visualise the scene.
Keep the number of characters to a minimum that way your story is more achievable. You can involves yourself and friends that way it is more fun.
This is where you write the actual story. It should last no more than 5 minutes of screen time and it should make people laugh. Test it on your friends. If they don't laugh, no one will.