If you haven't filed yet, go to the File section of TurboTax, and on the How do you want to pay your federal taxes? screen, select Request an IRS payment plan.
If you already filed, or you can't find this option in TurboTax, you can apply for a payment plan (Form 9465) at the IRS Payment Plans and Installment Agreements website. Make sure you've filed your return before applying through their site.
See this TurboTax help article for more information.