You have to calculate an NOL manually (link below); TurboTax does not calculate NOLs.
https://www.irs.gov/publications/p536#en_US_2020_publink1000177328
If you actually have an NOL for 2020, then you have to carry back the entire amount of the NOL to five years before the NOL year (2020 in this instance) and then carry any remaining NOL forward.
See https://www.irs.gov/publications/p536#en_US_2020_publink1000177354
Note that you can also waive the carryback period.
