You don't enter anything for the new deduction for seniors. TurboTax will give it to you automatically based on the birth date that you entered in your personal information.
The deduction for seniors is a deduction, not a credit. It reduces your taxable income, not your tax. The maximum deduction is $6,000 per person, but the maximum is gradually reduced over certain income levels, so you don't necessarily get the full $6,000.
