Course Builder is an alternate way to build your course and then make changes to it without using the Content editor in Brightspace. Many who use Course Builder think it provides a cleaner interface in which to see your entire course in a small area of screen space.
This is a brief navigation video of Course Builder.
Here’s an interface overview. https://documentation.brightspace.com/EN/le/course_builder/instructor/course_builder_interface_overview.htm
If you would like to get started using it and have questions, contact Paul Keys at email@example.com.