That should be done automatically by the program, provided you made the proper selections (e.g., that you materially participated); the result should appear on Line 4b of Form 8960.
If you have done so and there appears to be an error, contact Support via the link below.
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
