One great feature of Blackboard Collaborate Ultra is the ability to share content such as documents and files, your computer screen or an application on your computer, web pages, or a blank “whiteboard.” You can also conduct polling of participants and place them into breakout groups. Read here for details on how to share a File in Collaborate Ultra.
To share content in Blackboard Collaborate Ultra you should have already inserted the tool link in the content area and created a session. Once you have done that you can join a session. In the session, you can share content.