Adding any built-in composite creates a root level 'Composites' container. User-created blank composites can also be added to the container. Any composite in this container can be used as a 'master' to create a new copy.
To create a copy from a master, use the Create Composite option from the Note menu or the map view background's contextual menu. Note that composites with no composite name are not included in the pop-up lists of possible available composites.