As you have already been told at least twice, Form 3115 is only supported in forms mode in TurboTax. There is no support for it at all in the Step-by-Step interview. To switch to forms mode click the Forms icon (at the top right if you are using TurboTax in Windows). In forms mode, click Open Form. In the space for the form name type 3115. Then select the form in the list and click the Open Form button.
