In order to use Webex Teams in Blackboard you must first activate "Classroom Collaboration" in your LMS course.
For details, Enable WebEx in your LMS Course
Important Note - Webex Teams should only be used for classes with less than 20 students.
Once Classroom Collaboration has been activated, you must create all Spaces you want the students to work in via the LMS. Spaces created outside the LMS (i.e. via the desktop application) will not populate the Team in Blackboard.
After you have made the Spaces needed, you can use the desktop application to interact with the other members of the Team and all other features/options are available.