If you need to adjust the number of sections in your course, here's how:

Add Sections

To add a section, hover between two sections and click on the Add section plus sign.

Delete Sections

Sections can be deleted one at a time or in bulk by using the Bulk actions link at the top of the page. To delete a section, click on the Edit icon associated with it, then click on Delete. 

CAUTION: All content in the section will also be deleted! You’ll be asked to confirm the deletion, so nothing is deleted until that happens. (And if all else fails, don’t forget the recycle bin!)