If you want to start building your course before new course shells are available to you in Blackboard, (more info here) we recommend you consider the Master-Child course feature. A Master Course is simply a template of a course and has no students enrolled.
You can request a Master course be created for each of the courses you are assigned to teach. You can then build your Master course and, when it is done and the academic course start date is near, copy the course content from the Master Course into one or more "Child" courses (the sections in which students are enrolled).
Alternatively, you might be assigned to teach multiple sections of the same course in the same term but DO NOT wish to take advantage of the course merge feature. In this case, you can build your course using the Master Course and copy the Master Course content into each of the Child sections so you do not have to create content for each section.
If you're not sure whether creating a Master Course is right for you, please review other Course Copying Options before requesting the creation of a Master Course.