So how would you go about making a plan like this? Well if you know a fair amount about business, you can. It will take some special calculations and some work but if you know how to put together a Profit & Loss Statement, you can probably do it.
A lot of resources nowadays provide ready-made plans for specific businesses and whilst this is handy, most business owners will recommend that you write the plan yourself. This is because writing a plan for your business actually forces you to focus on what you want from your business and how to achieve your goals. When looking back on your initial plan for reference, you shouldn't necessarily assume that your initial assumptions and predictions will be correct, they are just that: predictions. You should be able to go back to your plan on a regular basis and view it and change it to relate to the actual current situation.