Where/how do I enter the itemized deduction for "Income with Respect to a Decedent deduction"?

Your deduction will be entered to Line 28 of Schedule A (not subject to the 2% limitation).

Click the Federal Taxes tab, click Deductions & Credits, click I'll choose what I want to work on, scroll all the way down to the bottom to Other Deductions and Credits and choose Other Deductible Expenses (click on Start)

1. Answer No to Generation-Skipping Taxes and No to Less Common Expenses
2. Answer Yes to Any other Deductions?
3. Enter the amount in the box next to Estate Tax Deduction