If using microwave popcorn, pop according to package directions and skip to step 2. Place large pot on the stove; add oil and 3 popcorn kernels and cover the pot. Turn the burner to medium high. When you hear the kernels pop, add the rest of the popcorn and the salt. Replace the lid. Swirl the pot as it pops. When the popping starts to slow, turn off the heat. Place the pot on a heating pad until the popping stops.