If you haven't filed yet, step through the File section of TurboTax until you reach the screen How do you want to pay your federal taxes? Select the installment payment plan option, Continue, and follow the onscreen instructions.
If you already filed, or you're unable to find this option in TurboTax, you can apply for a payment plan at the IRS webpage below. (Make sure you have filed your return before applying)
https://www.irs.gov/payments
