Retirement tax questions

If I understand your situation, you don't record the after-tax deposit on your tax return, but you note the presence of after tax deposits (called "basis") when you receive the distributions from the retirement account.

When you enter the 1099-R for the distributions from this account, TurboTax will ask you if you had made any after tax deposits.

Here is an example of the screen from the desktop product:

Note that it asks for this late in the 1099-R interview, so have patience. Also note that the screen in the Online product product probably looks different, so be flexible.