Cut a circle in the bottom of the pumpkin, and use an ice cream scoop to remove the pumpkin’s guts. Level the inside surface of the cut circle with a knife; this allows a candle to stand easily on a level base.
Tape the printed stencil to the pumpkin. Make closely-spaced pin pricks along the stencil lines with a push pin, piercing through the paper to the surface of the pumpkin.
Remove the printed stencil and carve along the pin-prick guide with a thin knife, cutting completely through the side of the pumpkin. Throw away excess pumpkin pieces.
Stand a candle (or electrical candle) on the bottom of the pumpkin, and set the carved pumpkin over it.