Students are enrolled in sections of courses. The difference is that a course like Math 6 will be taught year after year. A section of Math 6 exists for only one year, taught in one particular room by a particular teacher to a particular set of students.
Select a course for which you want to create section. In the lower right-hand corner of the course form, click on the New button.
The section form opens.
Choose the teacher from the dropdown menu, set the period if desired, and then click OK.