Need a help

can anyone tell me a solution. I have 4 tables are connected togather note,teacher,student,class

note table has note id, student id, teacher id , note_req,school_date.
teacher table has, teacher_id,teacher_name
student table has student_id,student_name
class has class_id,note id, student id, teacher id. date_of_class

1. I have inserted values into 3 tables which are student, teacher and note
2. I want to know how to insert same values which are primiry keys into class tables and if note_req = 'YES' insert a date value into date_of_class
the date_of_class must be school_day +90 days

I hope you understand what I am writting