Save, Update, Delete Function in School ERP in C#

Sir, I am doing a School ERP Form.

I have about 21 forms in my project.

I want your help to function Save, Update, Delete in two forms; frmStudent, frmSchool.

please find the attachment with this and extract the file.

the attachment includes my forms with class files(student Form) and database(DbSchoolDetails) I using in this project.

then run the form by connect to the database.