When you decide what type of business you want to plan, you go out and get information about how to run that business, set it up, organize, sell the product, make the product or purchase it, budget and finance the business and many important legal aspects llike patents, trademarks, copyrights, and business structure.
To develop your business plan you need to make decisions like:
Formal Planning Requirements;
Business Purpose/Mission Statement
Business Name and Licensing Requirements
Business Setup statement as to type of business structure
APPENDIX: including Articles of Incorporation, or S-Corp, or LLC Agreement, attorney and CPA determinations, filing of Fictitious Name, and EIN (Tax Number)
Principals (Owners,Investors) and Resumes
Marketing and Demographics
Staffing or organizational plan
Financial Plan including Financing Arrangments
Various Schedules And Graphs demonstrating payback, marketshare, strategic plan etc.
A lot of good info is found at the small business administration links below
