Bookable/assigned courses
Some of the courses you only want to make available to selected learners: you assign them the course, but learners themselves cannot search or book this course by themselves. Neither can they sign out of the course assigned by them by an administrator.
However, for other courses you might want learners themselves to discover & book the course, akin to the procedure described here.
Once the learner discovers the course & accesses the detail view of it, he can book it and gain access to the course's learning contents.
Once booked, the course status changes to "booked" and the user gets the possibility to give up on taking the course by clicking on the Stornieren button
If an admininistrator assigns this course to a learner, the learner can still cancel the booking at any time. So if you want to assign mandatory courses to your learner group, you need to make sure that the "assignable" toggle is deactivated in the course detail page in the Administration Panel