Here's how to make kettle corn at home in a large stock pot:
add 1/4 c vegetable oil in the bottom of the stock pot. Add 3 kernels of popcorn. Cover with lid and wait until the three kernels pop. Then add 1/2 cup popcorn kernels and 1/4 c sugar. Cover again. Leave on heat for 5 seconds, shake (pretty hard) for 3 seconds. Repeat. The kernels will start popping in about 1 minute. The whole pot will pop withing 3 minutes. remove from heat when the popping slows. Salt to taste.
If you do not have a large stock pot, you can use a large saucepan with 2 T oil, 4 T corn, and 2T sugar. I have tried using olive oil, but have found it does not seem to cook as well.