You can add Form 1099b by following these steps:
1. Sign into your account and select your current return
2. Select Tax Tools on the bottom left and then tools (see attached Tax Tools)
3. Select Topic Search (see attached Topic Search)
4. Search for 1099b and select Go
This will take you to the interview process Which begins with Did you sell any investments in 2017?
Follow this interview to enter your form.