Selecting the contents of a folder is mainly done using the mouse:
The objects to be included in the folder are selected in the corresponding dialog boxes.
While keeping the mouse right button pressed, drag the selected objects to the place chosen. The cursor changes into an icon representing the type of object moved (for example, a palette when a file or chapter object is moved from the Palette dialog box).
When the selected objects reach their target location, release the mouse button. The objects are then added at the chosen location.
This operation is known as a drag and drop operation.