Please refer to Copy Content from Other Courses for more information.
1. Go into your new Blackboard course.
2. On the Course Content page, select the three dot menu next to the search option on the Course Content page. 
3. Select Copy Items from the menu.
4. Click the checkbox the the left of the previous course you want to copy it's contents..
5. Select Start Copy.
For more information, please refer to Copying Content from Other Courses.