I agree with the other responses to this question. I'd like to suggest that you look seriously at developing a lean business canvas. Through this, you'd start to see a variety of hypothesis that you need to validate through the discovery interviews. I'm currently going through a Venture School program that is guiding us through this exact exercise. Two books that are highly recommended are Business Model Generation Book and StartUp Owner's Manual. I would also recommend searching for the Strategyzer videos on YouTube. All of these are filled with excellent information about testing your assumptions related to a startup. It will also outline how to pivot and iterate to further develop your ideas, leading to a higher likelihood of success. Good luck! Happy to discuss further if you have other questions.