To edit a Group, navigate to the Settings and click the User & Groups tab, followed by the Group sub-tab.
The Group List page will be displayed, showing the different groups and the users who belong to them.
Find the group that needs editing and click the Edit symbol (it appears as a pencil). From here, the name of the group can be changed. Hit the red Edit button to edit the members of the group.
Click on the members to select them from the group. Click them again to deselect them.
Click Save to finish editing the group.