In TurboTax, type "capital loss carryover" (without the quotes) in the Search box, then click the link that says "jump to capital loss carryover." On the screen that asks "Did you have investment losses you couldn't claim in 2018?" click Yes. The next screen asks "Do you know your capital loss carryover amounts?" Select No and click Continue. It will then prompt you to enter information from your 2018 tax return, and it will calculate the capital loss carryover for you.