https://help.gosimpletax.com/hc/en-gb/articles/360000026560-Losses-carried-back-to-previous-years

https://help.gosimpletax.com/hc/en-gb/articles/360000026560-Losses-carried-back-to-previous-years

Click on + Group Expenses     Select Tax Adjustments       Select the category Current Year losses to carry back to previous years