Each of your online courses will have most of the same elements that a face-to-face course would have, including a professor, a syllabus that outlines readings, assignments, projects and other deadlines, and a way for you to turn in your homework and take tests or quizzes. It will also have a discussion board where students post and respond to topics, and you can even contact your professor or other students in the virtual classroom.
The key difference with online courses is that you will need to pace and motivate yourself to complete the coursework on your own. While your professor will be present through lectures, assignments, grading and feedback, and your conferences via email, video chat or other means, you will not have the consistent routine of attending class to keep you focused on deadlines, as you might in a face-to-face course.
This also means more freedom to structure your study time as you please, however, and work in your online course whenever it suits you best.