Not a Chrome user here. Is that like container tabs? Or more like how Windows will group windows of the same program when your task bar is full?
So far the tabs work much the same as ungrouped ones. There is a small coloured button to the left of the group with the name, and the tabs in the group are underlined with the same colour.
But then you click the button and the tabs all collapse.
The nice thing is when expanded they are just like every other tab, not hidden away in a folder, or some menu or modal. But then you can clean up with the press of a button.
Lack of Tab Groups is what stopped me from switching to Firefox last year.