Populating a picklist another form

Populating a picklist another form

I am creating an App for ATTENDANCE MANAGEMENT for a School.

I have the forms:
- Students (Form1)
- Classes (Form2)
- Attendance Management (where I monitor the ATTENDANCE of students PER CLASS) (Form3)

In the ATTENDANCE FORM (Form3) I have the fields:

- Class (where I specify the student's Class)
- ATTENDANCE LIST (The problem is here, as it is BRINGING ALL STUDENTS FROM ALL CLASSES)

PROBLEM: I want this ATTENDANCE LIST FIELD to only bring STUDENTS FROM THE CLASS I SPECIFIED IN FORM4. How do I do that?