@JonPaul is absolutely correct. Don't go at it yourself--the perspective, challenges, and guidance you'll get from an experienced financial modeler is invaluable in sculpting your business model into one with the highest potential for success. It isn't so much about the model itself or how you present the numbers (although following convention is usually a good idea) but what's most important is that you're able to confidently and competently articulate the key activities, assumptions, and related financial metrics that make your business model successful. And that you have qualified empirical market dats to support your assumptions. The process of constructing a bottoms-up financial model will, by nature, force you to answer those questions and also test the outcome. You can't achieve the same thing by simply typing a handful of numbers into a generic template.
I've been CFO and financial modeler for dozens of startups through the fundraising process and have several equally qualified and experienced colleagues who exclusively provide this valuable service to entrepreneurs. Reach out to me if you want some intros to qualified folks who can help you with this.