Each course consists of 2-5 hours of video content which is split up into individual lesson videos that you can watch and re-watch at any time. In addition to the lesson videos, sometimes each course has a downloadable PDF workbook that you can use to supplement the videos and a student group that you can use to exchange feedback and discuss the lessons.
You can take the class at your own pace, so the number of weeks it takes to complete the course will vary.