To add or update the roll no/number of the students, follow the steps given:
Step 1:
Select the SIS module and then select the Update Student Details under the Enrollments menu.
(SIS-->Enrollments-->Update Student Details)
Step 2:
Select the respective Class-Section and click on Get. Under Student Details, select the Student Roll Number
option. Select the respective student and update the roll number and click on Submit.