php – How to create an edit page for each record?

Hello, I have a school report system in PHP where the responsible person records the students. The problem is in the modification page of the student, I can not set a single student, the link of the page appears the ID of the student selected but in the page they appear all those which have been registered by the user. I've already tried to put the student ID in the selection, but that does not work either.

If anyone can help, thank you very much.