It depends on the course you have selected. There are two types of courses:
- Self-paced - you can start them any time you want and follow the course calendar for closing dates. You usually have as much time as you need to complete these courses.
- Live courses - they have fixed start dates and deadlines for the different assessments.
You can find this kind of information directly on the course page that you are about to start. Below you will see an example of a live course with its deadline for registration
If you select a live course, please be aware of the starting date. If you missed the starting date, you may have to choose another course. This may also mean waiting for the next session of the course. If the course you selected has already finished, it will appear as Archived - this means that the course is no longer supervised and you cannot get a certificate for it, though the material is in most cases still available.
When you are taking a live course, always pay attention to the different deadlines of assignments.