In this section

I do not know if the grade I received is good or not?

Standard Grades are graded numerically with 1 being the highest grade and 7 the lowest:

1-2 Credit
3-4 General
5-6 Foundation
7 Course complete

National Courses - Intermediates 1 & 2, Higher and Advanced Higher are graded alphabetically with A being the highest grade:

A
B
C
D Grade D is an award on its own right. Grade D is awarded
where all Units of a course have been completed and where the
external assessment (exam) score is normally between 45% -49%.

Some National Courses, including those at Access 2 and Access 3 don't have grades, but any that you have achieved will be listed beside other Courses or Standard Grades.