Your system appears to be equivalent to a semester system in which 8 classes are taken per semester. Each class listed on your transcript shows 5 credit units, which would be the same as a normal semester class. They are just arranged differently from how they would be in a typical semester system (that is, in each semester, it looks like you are taking only 4 subjects but you get a whole year of credit for each one).
So to calculate your GPA, I would simply count up the grades you received (number of As, number of Bs), ignoring +/- as that is not relevant, and also ignoring the way that the classes are grouped on your transcript. Then use the calculator.