as @Critter-3 posted the loss from the S-Corp gets reported on your 2019 1040. then you had to determine if your 1040 showed a NOL for that year. (unlikely if adjusted gross income is greater than $0).
here's a link to a worksheet to compute if you have an NOL
https://www.irs.gov/publications/p536#en_US_2019_publink[phone number removed]
if you have an NOL you can make an election to waive the 5 year carryback. if you don't waive the carryback you would have to file amended returns starting with 2014 any remaining NOL gets carried forward to 2015 and so forth. the IRS allows a late election as follows
Late Waivers of 2018 and 2019 NOL Carryback Period
A taxpayer generally must file an election to waive an NOL carryback period by the due date, including extensions, of the income tax return for the year in which the NOL arose. However, the IRS allows taxpayers to file late waivers for NOLs arising in tax years beginning in 2019. The election to waive the carryback must be made by the due date, including extensions, for filing your 2020 income tax return. the election to carryforward the 2019 NOL must be separately stated.
The election statement must state that the taxpayer is electing to apply § 172(b)(3) under
Rev. Proc. 2020-24 and the taxable year for which the statement applies. Once made,
the election is irrevocable.
