You can follow the Steps below:
STEP 1: Flip your assembled puzzle over so the back face is up.
If you have difficulty flipping the puzzle over, we recommend sandwiching the puzzle in between two pieces of cardboard, and then flipping it over onto its back. If any pieces come loose, simply replace them before STEP 2.
STEP 2: With the picture - side down, lay out the permanent adhesive sheets on the puzzle back to see how you will apply them. Trim if necessary.
Overlap each sheet about 1/2 inch (1.3 cm). Do not extend adhesive sheets beyond puzzle edges - keep the adhesive edge 1/8 inch (.3 cm) away from all the puzzle edges.