How do I calculate early projections for my business plan?

Good luck to you. Use the resources at this Entrepreneur.com site to help you. Use business plan software to help you, the best of it offers you a tool that helps you organize and keep track of the plan, helps you with the math and finance of your numbers, but respects the fact that every business is unique and every business plan is unique. Good software is out there, and I won't recommend anything specific because I'm biased. Some other free web resources I'm very involved with are bplans.com and www.hurdlebook.com.