The regions that are included in agenda templates are designated as either regular or reserved.
These regions are automatically included in a meeting when you create the meeting.
These regions are not automatically included in a meeting when it is created. The region can be added to the meeting any time after the meeting is created.
If your agenda template includes any reserved regions they will be listed in the menu with all regions to add. Reserved regions appear below all regular regions.
Determining which regions should be regular and which should be reserved is up to you. In determining, you should consider if it is best to have the region included automatically for every meeting and then delete it if it is not necessary for a particular meeting, or if it is best to keep the region from being added automatically, and then just add it when necessary