Business Plan Writer opens the ‘Words’ section by default, with its big text box in the middle where you can write your stuff. 

The Table of Contents on the left-hand side can be changed, and by altering it you are actually altering the structure of your own business plan. 

On first launching, Business Plan Writer displays its default business plan structure (which you should take as a starting point only for your own business plan), but before deleting sections it might be worth your while to move through the skeleton business plan section-by-section to see the corresponding explanatory notes and view what each of the three sample business plans have in them (you can copy and paste from their text box into your own text box and then edit to make it right for you).