You’re writing for fun! Fantastic because that’s really the excitement in it for most of us. But there is a structure to screenwriting. It’s there not only for its own sake but it’s there to help you develop and bring out the story in such a way that it will be appreciated by an audience told through film. I found reading “Save the Cat” by Blake Snyder was a simple book that put it all together for me. A friend of mine said I should read it because Paul Haggis - Million Dollar Baby - advised him to read it. Stay in touch!