On the CWI website, look for the "Log In" dropdown on the top right and move your mouse over it to view your options. Choose "Blackboard."
Once you are logged in, locate the course you need and click to enter the course site. Every Blackboard course site is a little bit different, so there's a little bit of detective work that often involved in learning the navigation of each specific course.
First, look for the left-hand navigation bar and click through each item on it, familiarizing yourself with the contents. You will often find sections with the your course syllabus and schedule, a content section with folders that include your week-by-week content, a section with assignments, quizzes and tests, and another with discussion boards, but these will vary by course.
For additional help with Blackboard, check their online Help Center for students or Blackboard Learn playlist on YouTube.