If you navigate to onCampus > Procedure > Academics > Course Sections Expand the Department and Click Manage Sections on a Course, you may not have an option to click + Add Section to create Sections.
This is usually caused by the Course being a 2 Term (or full year) Course, and being in the Second Term (or any term other than the first). To fix this, you will need to toggle back to the First Term to be able add a Section to a Course.
To do this, navigate to:
onCampus > Procedure > Academics > Course Sections, and filter for the School Level and First Term
Expand the Department the Course is in
Click Manage Sections to create sections for the course