In this mode you can execute single Task on the currently selected Object(s) / Text / Table in the InDesign – or even process whole document.
It’s like applying different Paragraph Styles to a different parts of a text – or Object Styles to a different object(s) – but you can do more than one thing at a time.
If, for example, you’ll select a Rectangle & a TextFrame – Task can align them as an Image & Description. Of course, you can create multiple Tasks and each of them can align Description differently.