Calendar event groups are a collection of calendars, events or categories from the Calendar Module.
Multiple calendars, events and/or categories can be placed into separate groups. Even multiple events from different calendars can be placed into a single group!
These groups can then be linked to various applications or utilities (see: Calendar Module#ModuleSupport)
Add Group
Name: The name of this group
Calendars: The calendars you'd like to use.
Specific Categories: Categories you'd like to use. To see categories you need to select at least one calendar that has categories. If "None Selected" then all categories is assumed.
Specific Events: The specific events you'd like to use. You will only see events listed from the selected calendars above. If "None Selected" then all events are assumed.
Remove Group
To delete a group look for the trash can icon 
Edit Group
To edit a group look for the pencil icon