I experience operational losses from my business last year. How do I report them? Turbotax only allows reporting of positive income.

You have a net business loss when you expenses exceed your income.  Usually if you have zero income, you have no business activity.  You must enter the income and deductions in TurboTax to correctly report to the IRS and show the net loss.  (There is an entry for Returns and Refunds which is entered as a positive amount but is subtracted from other business income).