Common App Education and Testing

I’m quite unsure of how do student’s who have studied in CBSE to fill in their grades and testing in the Common Application.
There’s also the point that CBSE is a bit, well, more difficult than the American educational system, as well as being partially a 10 point GPA and partially having no grades at all, but percentages. So how does a person who studied in CBSE fill in Common App?

Thank You.