you can't import. however, you should look at the actual 1099-B. in 2020 TurboTax offers a summary section to enter type A and/or D transactions each type as on its own line provided there are no wash sales. any trades with wash sales would need to be manually entered as a separate transaction
if you want to mail in the 1099-B then you can enter each type as a single line item with adjustment code M
you then mail in the 1099-B with form 8453 following the filing instructions closely. make sure the 8949 line is checked on the 8453
https://www.irs.gov/pub/irs-pdf/f8453.pdf
if neither option appeals to you, you would need the services of a tax pro.
