I hope you didn’t get your hopes too high. There is no script. ChatGPT is only “working” while it is formulating a response to your prompt. Your prompts and its responses are the only data involved. You can’t ask it to work on something while you’re away. Well, you can, but it won’t.
That’s not to say that Large Language Models (LLMs) are incapable of writing a script, but it would be MUCH more involved on your part. text-davinci-003 would be your best bet, but you’re going to have to go through some trial and error, and editing, and depending on the length of the screenplay, you’ll probably have to iteratively summarize it as well.