For the beginners level (A1), the course is fully on the Internet. So that you can register and start the course at any point of time.
As soon as you register, you will have access to the full course content. And if you chose a package with a teacher, a teacher will be assigned to you, and he will be mentoring you for the following 6 months.
The course content has a lifetime validity, so even if you need to take a break from your learning, you will be able to come back to where you stopped later on.

For the other more advanced levels (A2-B1), we organize on a per-demand e-classes with one teacher and a group of teachers connected using a video-conferencing platform. The course is then similar to a normal classroom course, but with the power and freedom given by the Internet.