Online learning offers flexibility that you may not have in a traditional in-seat course. For many of us, that flexibility is what allows us to take classes. We set the schedule for when we will be "in class" attending to the course content, participating in discussion, and learning. Although there may be virtual "live" class meetings, for the most part, you will be directing your own time.
An online course is not a correspondence course, which are usually not designed to be self-paced, independent studies. In an online course, you will have course reading expectations, assignments with due dates, contact with your professor and your classmates, and maybe even group assignments. The course will have a directed pace, and everyone will be expected to follow the course calendar.
However, vital to success in an online course is your ability to be an independent learner. You will need to be self-directed and very organized so that you keep up and stay engaged. It is very easy to fall into the "out of sight, out of mind" mentality when you don't have a weekly "place" to show up and face your professor.
Please spend some time with the link. You should then have an idea of what you might expect in an online course and can hopefully develop some strategies for how you will manage.