As you can tell by the sample names given to the groups you usually grant a group the minimum level of permissions required to do their job.

Click the [ Set Permissions ] button. Second from the top right.

You grant access to a funtion by clicking on a check box. Uncheck the box to deny access. In the example above (look to the center of the grid) users in Group 3 (Supervisors) may Modify Violations, but only people in Group 9 (Administrators) can Delete a Violation.

Clicking the Name of the user group allows you to view the people who are a part of that group.

Clicking on the group number filters the list to the left so you only see the functions allowed for that group.