4. Once you do that, you should see the area SURROUNDING the area you painted in QMM selected. You may now edit the image.
You may delete the background by hitting the delete key, leaving you with just solitary image - Figure A.
If I want to change the rose itself. I would go to Select>Inverse, and only the rose would be selected - Figure B.
Or, with the rose selected, I can choose to cut it out entirely, and paste it in another document - Figure C.