When you have a small business, you typically will not be using the 1099-K entry. Rather, the amounts from 1099-K will already be included in your sales. You can enter the income reported on your Form 1099-K as self-employment income on Schedule C, the same as you would report cash, checks, etc.
See this article for more information: IRS Form 1099-K: What Online Business Owners Should Know
