What does the icon with nine small boxes do?

I am brand new to Figma and when I have selected as a group items, I see this small icon in the corner and when I click it, the items I’ve selected as a group ‘blow apart’. I’m sure it’s useful but can’t find out where to look to learn what it does! HELP the newbie pls :slight_smile:

The blue icon helps you to allign the items horizontaly and verticaly in your selection.

It helps you reorder your components in a neat way