Login to blackboard
Click the Courses Tab
Type the first part of the course ID (the course ID will start with EDU, PSY, MATH)
Click Go and look for the course ID that matches yours
Once you've found the correct course ID click the ID link such as EDUC102A
On the left side there should an Enroll button/link.
You are now enrolled and will see the course on the main page
If you are unable to enroll by this method please ask your instructor to enroll you in there course.