Do I enter a 2019 Net Loss from Line 31 Form 1040 in 2019 Net Operating Loss Carryover section or enter as a negative figure in Other Income?

Line 31 of Schedule C?  If so, neither.

Was there other income on the 2019 return that the loss could be used against?  If so, then that loss was already used (assuming you were "At Risk", which almost everybody with a Schedule C is "At Risk").

If the Schedule C loss offset all of your other income so that your 2019 AGI was negative, then you may have a Net Operating Loss (NOL).  TurboTax does NOT calculate NOLs or anything related it to, so you may want to go to a tax professional this year.