Need some info on 글쓰기 screenplays...

I have 더 많이 than one 질문 about screenplays, and here they are:
-I can't get a screenplay software to download because I'm stark broke, so does anyone know the basics of screenplay software?
-Who do I go to with a finished screenplay?
-How do I put a patent on a screenplay and do I need to put the patent number on the screenplay?
-What do 당신 call a person who writes screenplays?
Thank 당신 for your time!