Get your taxes done using TurboTax

The adjustment screen is a few screens past that.  Click on Done, and then you will see "Was this a sale of employee stock?"  Since it was RSUs, if they value was properly reported on your W-2 when issued, and you know the correct stock basis, you can answer no, and on the next screen you can indicate that "The cost basis on my statement is incorrect".   Checking that will cause the program to reveal a "Corrected cost basis" box where you can enter your correct stock basis.  (See screenshot below.)  Or you can indicate it's employee stock and the program will walk you through the entry.