Grouping is when you have two separate items joined together as one. For example, you may want to have students drag a text box and a shape tool together like in this example:
To do this, highlight both items. Then click on the ellipsis on the upper left corner and choose “group.”
Alternatively, you can use the shortcut key Ctrl + G (or cmd + G on Mac) after selecting the items.
To ungroup: select the group, click the ellipsis on the upper left corner and choose "ungroup".