Writing film scripts is very different from writing novels or journalism or any other kind of writing. This is because it's not really writing. It's a PLAN. Like an Architects Plan. The dialogue is the only bit that really survives, and even that gets changed by the Director or the Actor or both. So if you want to write and have what you write filmed exactly, then you have to Write and Direct. Lots of people want to do this, but God made very few creatures who are able to do this. This is because the personalities of Writers and Directors are so different: and even when such a person exists, usually one side of that person fails in the end. Unless they are one of the few i.e. A BRILLIANT ONE.