For more in depth and comprehensive instructions, please see below:
Firstly, compute your gross sales. Your gross sales are the total receipts from all of the goods that you have sold. You then subtract the purchase price of the goods. You can then subtract your operating expenses in order to compute your Incremental Net Operating Income. Your Net Operating Income is calculated by subtracting your operating expenses from your gross profit.
Be aware that very often some expenses are overlooked, for instance, insurance expenses and other kinds of administrative costs. It is these of costs that all add up to your overall operating expenses.
Furthermore, please note that the above step has been oversimplified. Every single last penny that has been spent in order to ensure the smooth running of your business is classified as a operating expense, and therefore must be accounted for.