By default Group Pages is enabled, and can be found by clicking on the Communication button in Blackboard. However, as the instructor you have control over what tools are available to students.
To change the availability of Group Pages, enter your Blackboard course, in Control Panel, click on Tool Availability under Customization.
In the Tool Availability page, scroll down until you find Groups. At this time you can disable Groups by removing the check or enabling Groups by add a check in the box to the right of Groups.
Click on the Submit button to finish the process.