Heat butter or oil of your preference in a dutch oven on the stove top at low heat with about 4 popcorn kernels and wait to hear them pop. When they pop, that's when you know the oil is heated enough for the rest of the kernels.
Once, butter has melted (or when oil is hot), add popcorn kernels, make sure that the popcorn is in a single layer, coated by the butter/oil. Turn up to medium heat (make sure that you DO NOT use high heat because the popcorn will burn! Trust me, that is no fun!). Making sure you have oven safe mitts on, you may want to give the Dutch oven a shift, to make sure the kernels are at the bottom and have a chance to pop.
When popping slows down, remove from heat and move to a bowl, sprinkle the popcorn while hot with salt, pepper and/or your favorite spices to taste.
Notes
Make sure that your Dutch oven is cleaned out thoroughly before starting, any residue may stick to the popcorn as it cooks.