START: background cat isn't behind mountain, footprints are obviously from a different source.
GOAL: background cat is visually blocked by mountain, footprints appear to be 'in the sand'.
SELECTION TOOLS: For selecting 'bumper' (covering part) from background or other assets.
EDIT/COPY and EDIT/PASTE: copy bumper from selection/paste bumper into new layer.
LAYER MENU:
The following video may be watched in its entirety, paused and followed step-by-step, skimmed our jumped through, or skipped altogether, depending on your familiarity and comfort level with getting from the 'START' to the 'GOAL'.