Django: how do I trigger 3 tables in postgresql

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PostgreSQL

Django

I am not really good when it comes in trigger trigger thing. I just want that if the admin update the StudentsEnrollmentRecord, it will trigger the SubjectSectionTeacher and it will save in StudentsEnrolledSubject.
can you guys help me solve this problem? especially in PostgreSQL Trigger

What I have tried:

CREATE OR REPLACE FUNCTION public.enrollmentrecord()
        RETURNS trigger
        LANGUAGE 'plpgsql'
        VOLATILE NOT LEAKPROOF
    AS $BODY$BEGIN
             INSERT INTO StudentsEnrolledSubject (Students_Enrollment_Records,Subject_Section_Teacher)
             SELECT a.id AS Students_Enrollment_Records, b.ID AS Subject_Section_Teacher
    		 FROM StudentsEnrollmentRecords AS a INNER JOIN
    		 SubjectSectionTeacher AS b ON a.School_Year = b.School_Year AND a.Education_Levels = b.Education_Levels AND a.Courses = b.Courses
    		 AND a.Section = b.Sections
    		 Where  a.EducationLevel=b.Education_Levels AND a.Course=b.Courses AND a.Section=b.Sections
    		 AND a.Student_Users=StudentsEnrolledSubject.Students_Enrollment_Records;
    END;
    $BODY$;
    
    ALTER FUNCTION public.enrollmentrecord()
        OWNER TO unidadb_admin;

And this is my Django model.py

class SubjectSectionTeacher(models.Model):
    School_Year = models.ForeignKey(SchoolYear, related_name='+', on_delete=models.CASCADE,null=True)
    Education_Levels = models.ForeignKey(EducationLevel, related_name='+', on_delete=models.CASCADE,blank=True)
    Courses= models.ForeignKey(Course, related_name='+', on_delete=models.CASCADE,null=True,blank=True)
    Sections= models.ForeignKey(Section, related_name='+', on_delete=models.CASCADE,null=True)
    Subjects= models.ForeignKey(Subject, related_name='+', on_delete=models.CASCADE,null=True)
    Employee_Users= models.ForeignKey(EmployeeUser, related_name='+', on_delete=models.CASCADE,null=True)
    Start_Date = models.DateField(null=True,blank=True)
    End_Date = models.DateField(null=True,blank=True)
    Remarks = models.TextField(max_length=500)


class StudentsEnrollmentRecord(models.Model):
    Student_Users = models.ForeignKey(StudentProfile, related_name='students', on_delete=models.CASCADE,null=True)
    School_Year = models.ForeignKey(SchoolYear, related_name='+', on_delete=models.CASCADE, null=True, blank=True)
    Courses = models.ForeignKey(Course, related_name='+', on_delete=models.CASCADE, null=True, blank=True)
    Section = models.ForeignKey(Section, related_name='+', on_delete=models.CASCADE, null=True,blank=True)
    Payment_Type = models.ForeignKey(PaymentType, related_name='+', on_delete=models.CASCADE, null=True)
    Education_Levels = models.ForeignKey(EducationLevel, related_name='+', on_delete=models.CASCADE,blank=True,null=True)
    Remarks = models.TextField(max_length=500,null=True,blank=True)

class StudentsEnrolledSubject(models.Model):
    Students_Enrollment_Records = models.ForeignKey(StudentsEnrollmentRecord, related_name='+', on_delete=models.CASCADE,null=True)
    Subject_Section_Teacher = models.ForeignKey(SubjectSectionTeacher, related_name='+', on_delete=models.CASCADE,null=True)