When you enter your ESPP sales, choose Employee Stock Purchase Plan as the type of investment you sold:
Indicate that your cost basis reported on the 1099-B form is wrong and that you need help finding the correct cost basis. You will come to a screen where you can indicate that the ESPP sale is not listed on a W-2 that is entered on your tax return. When you do that, the discount will be reported on schedule 1 on our tax return as other income.