Gee Scriptwrite you sound so bitter and desolate, my heart pumps purple pee-pee. Stop lying on the soft, split, fat part of your lower back and buy Lew Hunter's Screenwriting 434.
Read it.
Read it again.
And again.
Write your precious screenplay. There's nothing more you need to know. Failing that, take a course or do you want McScreenWrite lessons, all fat and salt and zero fibre?
Man you give this craft a bad name.