On the Enrollments page, select Enroll Users. On the Add Enrollments page, if you know the users' exact usernames, type them in the Username box separated by commas. If you don't know the usernames, select Browse to search for users. Select the check box for each user to enroll, then select Submit.
Enable Guest access in your course.In the lower left Control Panel area, click Customization, select Guest and Observer Access.For 'Allow Guests' click the circle next to Yes.Click Submit.
Allow guest and observer access On the Control Panel, expand the Customization section and select Guest and Observer Access. On the Guest and Observer Access page, select Yes for Allow Guests and Allow Observers.
When checked, Guest access enables attendees that are not enrolled on your Blackboard course to attend the Collaborate Session. Decide if you want guests to join as participants, presenters or moderators. Complete the rest of the session details. Copy the Guest Link URL and send it to your attendees.