From your Blackboard Collaborate page, click on "Create Session"
On the right side of your screen, you'll see a settings menu for your session. At the top, you'll enter a title for the session. Beneath that are settings for the time frame of the session, default guest role, and attendance options. You'll want to set up the times for your session, or you can make it ongoing or even recurring. Click save at the bottom of this menu to create your session.