Sure thing Simon! You have a few options as you can see there.

I'm assuming you created an account. If you have, you should go here and click Add new students. Once you've added students, you can create your class.

Go here and click Add new class, follow the instructions after that. The third step allows you to add your students to the class, after which your students will receive a notification telling them they were enrolled in your class. After that, you can start assigning work to them.

Those are the basic steps, this article covers it more in depth:

https://khanacademy.zendesk.com/hc/en-us/articles/115000778952-Guide-to-your-new-Coach-Dashboard-managing-classes-rosters-and-more-

Let me know if you have any further questions, hope this helps!

Thank you for your feedback. However, adding students is the crucial point I don't know how to handle. I cannot send an email invitation since they have not registered with it. They already have a Khan Academy account. So I cannot choose that as well. However, there are no other rostering options. So what can I do? Can students enter their email addresses in their existing accounts?

Yes, your students can add their emails in settings if they are older than 13.

There is another way I forgot to mention. Once you create a class, you will be given a Class code that your students can add on their own accounts like so:

1. Go to your coaches tab on your profile.
2. In the first box, you can input a class code. My class code is [insert your code].
3. After that, your account will be added to the class.

This is likely the the quicker option since the students can do all the work. ;)