Objects can be grouped so that when you select one in the Main View, all will be selected together for operations such as Move, Rotate, Mirror, Cut/Copy/Paste, etc.
Use the Edit menu->Group or ‘Ctrl-g’ for this.
Note: When items are grouped, they are still individually selectable in the Object View, and can be edited singly if selected.
If you have a design selected when grouping is performed, the design is part of the group. This means sequencing and copy/paste operations will be done at the design level. If you want all the objects from a design, but not the design itself, make sure to check the Object View to see that the design is not selected.
The Edit menu->Ungroup (Ctrl-u) can be used to ungroup objects.
You can group selections that contain sub-groups. Ungrouping will not ungroup the sub-groups – those will have to be ungrouped with a separate ungroup command.