First, open the student record.  This can either be by searching (Note, newly added records do not appear in the search until the following day) or find the student within the student list.  

Note: Images in this article are from a fictitious record in a dummy test database.

Click Enrolment on the Student Details Menu.

Locate Key Data panel on the right (you may have to scroll down).  Click on the Edit symbol circled.

Inserting a specific UPN?

Just type the number into the UPN field and click Save.  If the UPN is valit will save the value and return to the record.

Need to create a Temporary UPN or insert a new UPN?

Click on the spyglass icon to the right of the UPN field.

Select which UPN you wish to create and select Go.

This will return you to the previous screen with the UPN populated but currenlty not saved.

If you are happy with the result, click Save.