This feature can be used by the author(s) to create any number of groups or classes. This will help the exam instructor to arrange exam in batches.
Author can create a group, add any number of candidates to that group and schedule the exam for the group. To use this option click "Add Group" in the main Author menu.
A new window will open which will require author to enter the group name and click "Ok".
The group created will be listed under "Link Candidate to group" field when you are adding/editing candidates.