I am looking for a financial modeling template for a homemade food delivery startup in the idea stage.
Boom! .... and you're out of business!
It's not quite how that works. Starting with a financial model doesn't help if you don't have the figures to plug in. From idea stage, the next step is to work on researching your marketing strategy so it can be validated. This step defines who your audience is, where you will find them, what they will pay under which circumstances, what they need, what it will take to persuade them to choose your service, and more. This defines what your service needs to be to exist. Then you can start applying financial information to determine whether what's required is less than what income is likely. At that point you know if your idea can become a business.
A financial model doesn't really help you very much at the start. A business plan on the other hand will help you tremendously. I recommend using the template you can download from SCORE and working through those steps first.