You enter box 4 on the same screen where you entered the 1099R. Didn't you enter all the boxes on the 1099R? The withholding will show up on 1040 line 25b.
To enter Federal or State Estimated Taxes Paid, including a state estimated payment made in January for the prior year, go to
Federal on left or at top (Personal for Home & Business)
Deductions and Credits
Then scroll way down to Estimates and Other Taxes Paid
Estimated - click the Start or Update button
Estimates show up on 1040 line 26.