You can get to the Groups view by navigating to the Grid View and selecting the Group Names tab under the Overview section. This will display all available groups that can be edited.
You can enable groups by clicking on the checkbox that is in the Enabled column. You can disable them by clicking the checkbox again once it is enabled. System and Protected groups cannot be enabled or disabled.
You can update the label of the group by typing in the textbox under the Label column. If the group is disabled, typing in a label will automatically enable that group.
To move a group between group numbers simple right-click on the row of the group that you want to move and click Move Group. This will bring up a dialog with all available options that you can move the group too if there are any. Click on the new group number you want to move the group to and then click Move which will move the group and then close the dialog.
Under the Visibility heading there are two checkboxes; one for User visibility and one for Plan visibility. The User visibility setting determines whether or not to display the group in user applications such as the Schedule application and Home application. The Plan visibility is similar in the sense that it determines whether or not to display the group on the Plan view. This is useful when you have groups for specialised purposes that you don't necessarily want to display drawn on the plan view.