To begin, access your Blackboard Assignment on your module, by clicking on the assignment link created by your instructor on your course:

When you are ready to submit your video assignment, rather than uploading a document as you might normally, choose to Write Submission > as pictured below:

Click on the three dots to expand the menu, and then find the + icon to access your Kaltura media library:

Select Kaltura Media Submission from the list.

By clicking Add New, you can upload a video from their machine, or record one via your webcam. Or if you have a video already created and  uploaded to your private Kaltura media library, just select it from the list by clicking Embed.

Once the student has added the video and selected it, it will appear in the page. They can now choose to Submit.  

The instructor can watch the video and mark it as they would any other Blackboard assignment, via the Grade Center.