How do I enter a course with more than 15 units?

So I was updating my UC App and I realized that there was a blurb at the side and instructions attached to it (which I didn’t quite get). I was really confused about this. I just entered all my courses in without a problem although all my semesters have more than 15 units. Can someone please clarify this?

I believe they are referring to an applicant attempting to add a single course that is worth 15+ units to a semester.

^ Yep. If you had one class that was 20 units, you’d have a problem. >15 unit semesters are fine.