As far as TTX software is concerned, You just enter that stock sale/loss in the software (along with any other stock,bond,mutual fund sales you may have) down in the Investment Income area on the Wages&Income page.
The software will first apply the loss against any other gains you might have for the year, and then, if any is left over, then "up-to" $3000 will be subtracted from any other ordinary income you have for the year. Any remaining loss $$ will be carried over to next year's taxes.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
