Start by writing a description of your business, including what stage of development it is currently in (conception, start_up, first year, mature, exit) and your plans for growth. Discuss the nature of your business, the main products and services you offer, the market for your products and services, and how and by whom the business is operated.
The main thing to remember in this section is not to provide new data, but to explain in detail data that has already been provided and to provide the support for that data.
Summary Section: This section is where you will be able to attach or explain any detail not applicable to the previous sections. This section should be used to provide the financial statements of the Principle's involved in the business and any other data you think an investor would be interested in seeing.
For an online business, a detailed and in depth business plan is usually not necessary unless you are trying to combine your online business with a traditional business. For most online business startups, the detail involved with planning a traditional business is not required. However, it would still be beneficial to you if most of the topics were still covered, even if only briefly. Having a written plan in front of you will help you to focus on important aspects of the business.