If you received a tax slip related to this loss, you just need to enter the slip. If you don’t have a slip, this is how to enter your losses in TurboTax Online:
At the top right of the page, click the "Find" icon (magnifying glass).
When the search bar appears, typein“cap”, select “Capital Gains and Capital Gains Deduction Profile” from the list, then click the “Go” button.
This will take you to the Your Capital Gains Profile page. There you can check off any boxes that apply to you. You can then continue through the pages and enter your loss information.