Quick Groups are a sophisticated solution to group documents by drag-and-drop and to print and export those Quick Groups as single documents or files of complete books for example
To add an existing text to such a Quick Group, you simply select it and drag it onto the selected Quick Group. Of course you can also do this by button and while creating a new document you can automatically have it added to a selected Quick Group…
How to create a new Quick Group
Use Menu > File > New Quick Group…