SQL & PL/SQL :: How To Use Cursors / Loops And Proper Syntax

homework assignment using pl/sql based on 2 tables I have created below? I am not sure of how to use cursors, loops and proper syntax.

ASSIGNMENT:

1. Create a PL/SQL Procedure (cursor to loop through the records, check the LastName, then update the grade table
where id=id on grade table)

Rule:
A
‐ LastName ends with a character between A‐F
B
‐ LastName ends with a character between G‐K
C
‐ LastName ends with a character between L‐P
D
‐ LastName ends with a character between Q‐T
E
‐ LastName ends with a character between U‐Z

Create TABLE Registration (RegistrationID number(10), SectionID number(10), CourseID number(10),
SectionNumber varchar2(10),
StudentID number(10), FirstName varchar2(20),
LastName varchar2(20), CourseNumber varchar2(20), CourseName varchar(20));
[code].....