I’d start with the SBA’s free business-plan guide if you’re turning an idea...
https://www.bookmarkingvictor.win/what-resource-should-the-description-recommend-share-its-name-or-link-plus
I’d start with the SBA’s free business-plan guide if you’re turning an idea into a workable plan. It walks through market research, costs, and financial projections, so you can spot gaps before you spend money or take the plan to a lender