If you'd like to leave a course, the teacher (course admin) must remove you from the course. Please contact the teacher in-person, or send the course admin a message through Schoology. To find the course admin of the course, click Members from the left menu of the course profile. The member with the yellow shield is the course admin.
If you'd like to leave a group, click Leave this group located at the end of the left menu in the group profile.