1) Go with your opencompas URL then you will get the login page, after that you have entered your ID and PASSWORD
2) After that you can see the dashboard, click on the student module as shown in the below image.
3) Then click on the student list menu, after that, you will see two admission number wise or class wise options, if you want to admission number the need to enter admission number or you want class wise then select class, after that you will get student list.
4) Then click on name of student, then you will get the edit button click on that button now you can edit the details