Where do I list my charitable donations from my 401K account?

You are confused about something.  401(k)s and IRAs are different types of retirement accounts, and QCDs are only permitted to be made from an IRA, not from a 401(k).  If the Form 1099-R provided by the payer has the IRA/SEP/SIMPLE box marked (which seems to be the case if you entered the form correctly into TurboTax), the distribution is from an IRA and is reportable as a QCD.  No other documentation is required with your tax return beyond the "QCD" notation on line 4b of Form 1040.

If the distribution was indeed from a 401(k) and the Form 1099-R provided by the payer does not have the IRA/SEP/SIMPLE box marked (contrary to the way you seems to have in marked on TurboTax's 1099-R form), the charitable contribution is not excludible from line 5b Form 1040 and your AGI, and your charitable contribution must be reported on Schedule A the same as you would a charitable contribution not made from some other source of funds.