On the Wages and Income page, scroll down to Edit (if you want to keep all the info, but change the amount from last year) or Add Investments (if you want to add a new payer).
If you choose Add Investments, on the next page, click 'Skip Import'.
On the next screen, choose the type of investment income you want to report (bank interest), and Continue.
The following screen will have entry boxes for you.
If you choose Edit, the next screen displays the info from last year that you can change.
Here's more info on How to Enter 1099-INT.
