Get the template.
Download the desired design, print it out, and then cut out the template with scissors.
Plan the design.
Consider how the pattern will fit on the pumpkin and how it will repeat. Tape it to the pumpkin. (You may need to cut slits into the perimeter of the template and overlap it so it conforms to the roundness.) Using an awl, a pushpin, or a T pin, prick every 1/8 to 1/4 inch along the outlines of the template. Then remove the template, but keep it for reference.
Gut the pumpkin.
Lit pumpkins need to be gutted. Use a serrated knife to carve a hole in the bottom or back of the pumpkin. With a fleshing tool or plaster scraper, remove seeds, pulp, and flesh.
Create the design.
Use linoleum cutters to scrape the pumpkin skin. Start with the outline of the design and work inward. For details, use a No. 1 or No. 2 blade. For larger areas, use a No. 3 or No. 5 blade. Scrape in the same direction in each section to keep the lines unified.