How to Insert,Update,Delete one table in join database using

Question

Hi
in my c# winform project I have a database with 4 table joined
i select data and show in datagrid view and want to insert,update
data in one table using datagridview and button in form
I have 3 question please help me
1- the data in datagridview show in dieffrent row
I want show data for each student in one row
2- how to insert data ( grade ) for each student using datagridview and click button in form
3- any better idea for this student system
please help me and slove my questions

my project uploded here

http://www.mediafire.com/download/uz8zya166dju5lq/studentsystem.zip