What is grouping plasmoid and where to use it?

EDIT: I managed to figure it out with the help of other members here and another stranger on the internet.

1. Can be used on both taskbar and desktop.
2. Needs to be in Add Widgets screen, first add Grouping Plasmoid to desktop and then drag and drop other needed widgets into it.
3. No sign of tiling option available still, top tab bar lets you change the one in focus.