Clean your pumpkin and dry it completely.
Fire up the gun and load it with glue.
Start by outlining the eyes, nose, and mouth with candy corn.
To apply the corn, squirt a 2"-3" line of glue and quickly apply the corn. You want the corn to go on in fairly random patterns. Or not. It's your pumpkin.
Now, just fill in the rest of the pumpkin with candy corn!