I always go straight for the prompt with this kind of thing - it's here: https://github.com/knowsuchagency/pdf-to-podcast/blob/512bfb...

It starts like this:

    Your task is to take the input text provided and turn it into
    an engaging, informative podcast dialogue. The input text may
    be messy or unstructured, as it could come from a variety of
    sources like PDFs or web pages. Don't worry about the
    formatting issues or any irrelevant information; your goal is
    to extract the key points and interesting facts that could be
    discussed in a podcast.

The way this uses different OpenAI TTS voices for the different roles is really neat!