Create a selected area using the tools
Activate the required tool. When the mouse hovers above a selected area, a cursor appears 
. In this case, the selection can be shifted. If at the same time you hold a Ctrl key down, a cursor appears 
. In this case, the selection will be shifted together with the selected area. When a Shift key is held down, a new selected area can be added to the already existing one 
. When an Alt key is held down, a new selected area can be subtracted from the already existing one 
.