Your first activity is to carefully read your course syllabus, which you will find as a PDF. You will be able to access it anytime you are online.
Check the technical requirements for this course (particularly the web browser) and be sure that your computer meets them. If you were able to play the Jack Dangermond TED Talk video from the Welcome Page, you should be able to play all lecture files in this course.
Next, review the assignment/course percentage breakdown and study the schedule and due dates closely. Take note of assignment and discussion forum due dates. It is your responsibility to monitor this for yourself.