In TurboTax, enter the description from your W-2's box 14 on the first field in the row. Enter the dollar amount and select the correct tax category that goes with that description.
If none of the categories apply, scroll to the bottom of the list and choose Other (not classified). Don’t worry. We'll figure out if it impacts your return or not. If we need more information, we'll ask you. There is no key to box 14 - - this box is for the employer, so whatever is in there only makes sense to your employer. Box 12 has specific codes, but not box 14.
Employers can put just about anything in box 14; it's a catch-all for items that don't have their own dedicated box on the W-2.