What is the most logical next event?

How to paint your selection in zoner photo studio 
Open your image in zoner photo studio. 
Locate the brush. 
This way you can save the selection in case it gets messed up later.

Available options:
(A). Break up the image that you aren't using into pieces. The longer you copy it, the more uneven the final product will be..
(B). Hold the roller away from you, keep your freehand pressing the work button. Put the brush you will use at the right angle onto the paint tube..
(C). It will be saved as a transparent png. Note the odd bits that aren't quite selected..
(D). Line up the entire window with the long, straight outside edge of the box. Gather some newspaper and a pencil and line the window with the newspaper..
(C).