It may be helpful to think of the Eraser tool as a
paintbrush that paints with Background
Color. It may be helpful to think of the Eraser tool as a
paintbrush that paints with Background
Color.
From the Tool Settings Panel, select the color, and size of the eraser using the Background Color controls. Erase sections of the image as you would paint with a paintbrush. The erased sections will be cut out down to background color.
Selecting the eraser size and background color